content: import time
  import typing
  
  import json
  import jsonpickle
  import logging
  import uuid
  from dateutil import parser
  from typing import List, Dict, Text, Any, Type, Optional
  
  if typing.TYPE_CHECKING:
      from rasa.core.trackers import DialogueStateTracker
  
  logger = logging.getLogger(__name__)
  
  
  def deserialise_events(serialized_events: List[Dict[Text, Any]]
                         ) -> List['Event']:
      """Convert a list of dictionaries to a list of corresponding events.
  
      Example format:
          [{"event": "slot", "value": 5, "name": "my_slot"}]
      """
  
      deserialised = []
  
      for e in serialized_events:
          if "event" in e:
              event = Event.from_parameters(e)
              if event:
                  deserialised.append(event)
              else:
                  logger.warning("Ignoring event ({}) while deserialising "
                                 "events. Couldn't parse it.")
  
      return deserialised
  
  
  def deserialise_entities(entities):
      if isinstance(entities, str):
          entities = json.loads(entities)
  
      return [e for e in entities if isinstance(e, dict)]
  
  
  def md_format_message(text, intent, entities):
      from rasa_nlu.training_data.formats import MarkdownWriter, MarkdownReader
  
      message_from_md = MarkdownReader()._parse_training_example(text)
      deserialised_entities = deserialise_entities(entities)
      return MarkdownWriter()._generate_message_md(
          {"text": message_from_md.text,
           "intent": intent,
           "entities": deserialised_entities}
      )
  
  
  def first_key(d, default_key):
      if len(d) > 1:
          for k, v in d.items():
              if k != default_key:
                  # we return the first key that is not the default key
                  return k
      elif len(d) == 1:
          return list(d.keys())[0]
      else:
          return None
  
  
  # noinspection PyProtectedMember
  class Event(object):
      """Events describe everything that occurs in
      a conversation and tell the :class:`rasa.core.trackers.DialogueStateTracker`
      how to update its state."""
  
      type_name = "event"
  
      def __init__(self, timestamp=None):
          self.timestamp = timestamp if timestamp else time.time()
  
      def __ne__(self, other):
          # Not strictly necessary, but to avoid having both x==y and x!=y
          # True at the same time
          return not (self == other)
  
      def as_story_string(self):
          raise NotImplementedError
  
      @staticmethod
      def from_story_string(event_name: Text,
                            parameters: Dict[Text, Any],
                            default: Optional[Type['Event']] = None
                            ) -> Optional[List['Event']]:
          event = Event.resolve_by_type(event_name, default)
  
          if event:
              return event._from_story_string(parameters)
          else:
              return None
  
      @staticmethod
      def from_parameters(parameters: Dict[Text, Any],
                          default: Optional[Type['Event']] = None
                          ) -> Optional['Event']:
  
          event_name = parameters.get("event")
          if event_name is not None:
              copied = parameters.copy()
              del copied["event"]
  
              event = Event.resolve_by_type(event_name, default)
              if event:
                  return event._from_parameters(parameters)
              else:
                  return None
          else:
              return None
  
      @classmethod
      def _from_story_string(
          cls,
          parameters: Dict[Text, Any]
      ) -> Optional[List['Event']]:
          """Called to convert a parsed story line into an event."""
          return [cls(parameters.get("timestamp"))]
  
      def as_dict(self):
          return {
              "event": self.type_name,
              "timestamp": self.timestamp,
          }
  
      @classmethod
      def _from_parameters(cls, parameters):
          """Called to convert a dictionary of parameters to a single event.
  
          By default uses the same implementation as the story line
          conversation ``_from_story_string``. But the subclass might
          decide to handle parameters differently if the parsed parameters
          don't origin from a story file."""
  
          result = cls._from_story_string(parameters)
          if len(result) > 1:
              logger.warning("Event from parameters called with parameters "
                             "for multiple events. This is not supported, "
                             "only the first event will be returned. "
                             "Parameters: {}".format(parameters))
          return result[0] if result else None
  
      @staticmethod
      def resolve_by_type(
          type_name: Text,
          default: Optional[Type['Event']] = None
      ) -> Optional[Type['Event']]:
          """Returns a slots class by its type name."""
          from rasa.core import utils
  
          for cls in utils.all_subclasses(Event):
              if cls.type_name == type_name:
                  return cls
          if type_name == "topic":
              return None  # backwards compatibility to support old TopicSet evts
          elif default is not None:
              return default
          else:
              raise ValueError("Unknown event name '{}'.".format(type_name))
  
      def apply_to(self, tracker: 'DialogueStateTracker') -> None:
          pass
  
  
  # noinspection PyProtectedMember
  class UserUttered(Event):
      """The user has said something to the bot.
  
      As a side effect a new ``Turn`` will be created in the ``Tracker``."""
  
      type_name = "user"
  
      def __init__(self, text,
                   intent=None,
                   entities=None,
                   parse_data=None,
                   timestamp=None,
                   input_channel=None,
                   message_id=None):
          self.text = text
          self.intent = intent if intent else {}
          self.entities = entities if entities else []
          self.input_channel = input_channel
          self.message_id = message_id
  
          if parse_data:
              self.parse_data = parse_data
          else:
              self.parse_data = {
                  "intent": self.intent,
                  "entities": self.entities,
                  "text": text,
              }
  
          super(UserUttered, self).__init__(timestamp)
  
      @staticmethod
      def _from_parse_data(text, parse_data, timestamp=None, input_channel=None):
          return UserUttered(text,
                             parse_data.get("intent"),
                             parse_data.get("entities", []),
                             parse_data,
                             timestamp,
                             input_channel)
  
      def __hash__(self):
          return hash((self.text, self.intent.get("name"),
                       jsonpickle.encode(self.entities)))
  
      def __eq__(self, other):
          if not isinstance(other, UserUttered):
              return False
          else:
              return (self.text, self.intent.get("name"),
                      [jsonpickle.encode(ent) for ent in self.entities]) == \
                     (other.text, other.intent.get("name"),
                      [jsonpickle.encode(ent) for ent in other.entities])
  
      def __str__(self):
          return ("UserUttered(text: {}, intent: {}, "
                  "entities: {})".format(self.text, self.intent, self.entities))
  
      @staticmethod
      def empty():
          return UserUttered(None)
  
      def as_dict(self):
          d = super(UserUttered, self).as_dict()
          input_channel = None   # for backwards compatibility (persisted evemts)
          if hasattr(self, "input_channel"):
              input_channel = self.input_channel
          d.update({
              "text": self.text,
              "parse_data": self.parse_data,
              "input_channel": input_channel
          })
          return d
  
      @classmethod
      def _from_story_string(
          cls,
          parameters: Dict[Text, Any]
      ) -> Optional[List[Event]]:
          try:
              return [cls._from_parse_data(parameters.get("text"),
                                           parameters.get("parse_data"),
                                           parameters.get("timestamp"),
                                           parameters.get("input_channel"))]
          except KeyError as e:
              raise ValueError("Failed to parse bot uttered event. {}".format(e))
  
      def as_story_string(self, e2e=False):
          if self.intent:
              if self.entities:
                  ent_string = json.dumps({ent['entity']: ent['value']
                                           for ent in self.entities})
              else:
                  ent_string = ""
  
              parse_string = "{intent}{entities}".format(
                  intent=self.intent.get("name", ""),
                  entities=ent_string)
              if e2e:
                  message = md_format_message(self.text,
                                              self.intent,
                                              self.entities)
                  return "{}: {}".format(self.intent.get("name"), message)
              else:
                  return parse_string
          else:
              return self.text
  
      def apply_to(self, tracker: 'DialogueStateTracker') -> None:
          tracker.latest_message = self
          tracker.clear_followup_action()
  
  
  # noinspection PyProtectedMember
  class BotUttered(Event):
      """The bot has said something to the user.
  
      This class is not used in the story training as it is contained in the
  
      ``ActionExecuted`` class. An entry is made in the ``Tracker``."""
  
      type_name = "bot"
  
      def __init__(self, text=None, data=None, timestamp=None):
          self.text = text
          self.data = data
          super(BotUttered, self).__init__(timestamp)
  
      def __hash__(self):
          return hash((self.text, jsonpickle.encode(self.data)))
  
      def __eq__(self, other):
          if not isinstance(other, BotUttered):
              return False
          else:
              return (self.text, jsonpickle.encode(self.data)) == \
                     (other.text, jsonpickle.encode(other.data))
  
      def __str__(self):
          return ("BotUttered(text: {}, data: {})"
                  "".format(self.text, json.dumps(self.data, indent=2)))
  
      def apply_to(self, tracker: 'DialogueStateTracker') -> None:
  
          tracker.latest_bot_utterance = self
  
      def as_story_string(self):
          return None
  
      @staticmethod
      def empty():
          return BotUttered()
  
      def as_dict(self):
          d = super(BotUttered, self).as_dict()
          d.update({
              "text": self.text,
              "data": self.data,
          })
          return d
  
      @classmethod
      def _from_parameters(cls, parameters):
          try:
              return BotUttered(parameters.get("text"),
                                parameters.get("data"),
                                parameters.get("timestamp"))
          except KeyError as e:
              raise ValueError("Failed to parse bot uttered event. {}".format(e))
  
  
  # noinspection PyProtectedMember
  class SlotSet(Event):
      """The user has specified their preference for the value of a ``slot``.
  
      Every slot has a name and a value. This event can be used to set a
      value for a slot on a conversation.
  
      As a side effect the ``Tracker``'s slots will be updated so
      that ``tracker.slots[key]=value``."""
  
      type_name = "slot"
  
      def __init__(self, key, value=None, timestamp=None):
          self.key = key
          self.value = value
          super(SlotSet, self).__init__(timestamp)
  
      def __str__(self):
          return "SlotSet(key: {}, value: {})".format(self.key, self.value)
  
      def __hash__(self):
          return hash((self.key, jsonpickle.encode(self.value)))
  
      def __eq__(self, other):
          if not isinstance(other, SlotSet):
              return False
          else:
              return (self.key, self.value) == (other.key, other.value)
  
      def as_story_string(self):
          props = json.dumps({self.key: self.value})
          return "{name}{props}".format(name=self.type_name, props=props)
  
      @classmethod
      def _from_story_string(
          cls,
          parameters: Dict[Text, Any]
      ) -> Optional[List[Event]]:
  
          slots = []
          for slot_key, slot_val in parameters.items():
              slots.append(SlotSet(slot_key, slot_val))
  
          if slots:
              return slots
          else:
              return None
  
      def as_dict(self):
          d = super(SlotSet, self).as_dict()
          d.update({
              "name": self.key,
              "value": self.value,
          })
          return d
  
      @classmethod
      def _from_parameters(cls, parameters):
          try:
              return SlotSet(parameters.get("name"),
                             parameters.get("value"),
                             parameters.get("timestamp"))
          except KeyError as e:
              raise ValueError("Failed to parse set slot event. {}".format(e))
  
      def apply_to(self, tracker):
          tracker._set_slot(self.key, self.value)
  
  
  # noinspection PyProtectedMember
  class Restarted(Event):
      """Conversation should start over & history wiped.
  
      Instead of deleting all events, this event can be used to reset the
      trackers state (e.g. ignoring any past user messages & resetting all
      the slots)."""
  
      type_name = "restart"
  
      def __hash__(self):
          return hash(32143124312)
  
      def __eq__(self, other):
          return isinstance(other, Restarted)
  
      def __str__(self):
          return "Restarted()"
  
      def as_story_string(self):
          return self.type_name
  
      def apply_to(self, tracker):
          from rasa.core.actions.action import ACTION_LISTEN_NAME
          tracker._reset()
          tracker.trigger_followup_action(ACTION_LISTEN_NAME)
  
  
  # noinspection PyProtectedMember
  class UserUtteranceReverted(Event):
      """Bot reverts everything until before the most recent user message.
  
      The bot will revert all events after the latest `UserUttered`, this
      also means that the last event on the tracker is usually `action_listen`
      and the bot is waiting for a new user message."""
  
      type_name = "rewind"
  
      def __hash__(self):
          return hash(32143124315)
  
      def __eq__(self, other):
          return isinstance(other, UserUtteranceReverted)
  
      def __str__(self):
          return "UserUtteranceReverted()"
  
      def as_story_string(self):
          return self.type_name
  
      def apply_to(self, tracker: 'DialogueStateTracker') -> None:
          tracker._reset()
          tracker.replay_events()
  
  
  # noinspection PyProtectedMember
  class AllSlotsReset(Event):
      """All Slots are reset to their initial values.
  
      If you want to keep the dialogue history and only want to reset the
      slots, you can use this event to set all the slots to their initial
      values."""
  
      type_name = "reset_slots"
  
      def __hash__(self):
          return hash(32143124316)
  
      def __eq__(self, other):
          return isinstance(other, AllSlotsReset)
  
      def __str__(self):
          return "AllSlotsReset()"
  
      def as_story_string(self):
          return self.type_name
  
      def apply_to(self, tracker):
          tracker._reset_slots()
  
  
  # noinspection PyProtectedMember
  class ReminderScheduled(Event):
      """ Allows asynchronous scheduling of action execution.
  
      As a side effect the message processor will schedule an action to be run
      at the trigger date."""
  
      type_name = "reminder"
  
      def __init__(self, action_name, trigger_date_time, name=None,
                   kill_on_user_message=True, timestamp=None):
          """Creates the reminder
  
          Args:
              action_name: name of the action to be scheduled
              trigger_date_time: date at which the execution of the action
                  should be triggered (either utc or with tz)
              name: id of the reminder. if there are multiple reminders with
                   the same id only the last will be run
              kill_on_user_message: ``True`` means a user message before the
                   trigger date will abort the reminder
              timestamp: creation date of the event
          """
  
          self.action_name = action_name
          self.trigger_date_time = trigger_date_time
          self.kill_on_user_message = kill_on_user_message
          self.name = name if name is not None else str(uuid.uuid1())
          super(ReminderScheduled, self).__init__(timestamp)
  
      def __hash__(self):
          return hash((self.action_name, self.trigger_date_time.isoformat(),
                       self.kill_on_user_message, self.name))
  
      def __eq__(self, other):
          if not isinstance(other, ReminderScheduled):
              return False
          else:
              return self.name == other.name
  
      def __str__(self):
          return ("ReminderScheduled("
                  "action: {}, trigger_date: {}, name: {}"
                  ")".format(self.action_name, self.trigger_date_time,
                             self.name))
  
      def _data_obj(self):
          return {
              "action": self.action_name,
              "date_time": self.trigger_date_time.isoformat(),
              "name": self.name,
              "kill_on_user_msg": self.kill_on_user_message
          }
  
      def as_story_string(self):
          props = json.dumps(self._data_obj())
          return "{name}{props}".format(name=self.type_name, props=props)
  
      def as_dict(self):
          d = super(ReminderScheduled, self).as_dict()
          d.update(self._data_obj())
          return d
  
      @classmethod
      def _from_story_string(
          cls,
          parameters: Dict[Text, Any]
      ) -> Optional[List[Event]]:
  
          trigger_date_time = parser.parse(parameters.get("date_time"))
          return [ReminderScheduled(parameters.get("action"),
                                    trigger_date_time,
                                    parameters.get("name", None),
                                    parameters.get("kill_on_user_msg", True),
                                    parameters.get("timestamp"))]
  
  
  # noinspection PyProtectedMember
  class ReminderCancelled(Event):
      """Cancel all jobs with a specific name."""
  
      type_name = "cancel_reminder"
  
      def __init__(self, action_name, timestamp=None):
          """
          Args:
              action_name: name of the scheduled action to be cancelled
          """
  
          self.action_name = action_name
          super(ReminderCancelled, self).__init__(timestamp)
  
      def __hash__(self):
          return hash(self.name)
  
      def __eq__(self, other):
          return isinstance(other, ReminderCancelled)
  
      def __str__(self):
          return ("ReminderCancelled(action: {})"
                  .format(self.action_name))
  
      def as_story_string(self):
          props = json.dumps(self._data_obj())
          return "{name}{props}".format(name=self.type_name, props=props)
  
      @classmethod
      def _from_story_string(
              cls,
              parameters: Dict[Text, Any]
      ) -> Optional[List[Event]]:
          return [ReminderCancelled(parameters.get("action"),
                                    parameters.get("timestamp"))]
  
  
  # noinspection PyProtectedMember
  class ActionReverted(Event):
      """Bot undoes its last action.
  
      The bot everts everything until before the most recent action.
      This includes the action itself, as well as any events that
      action created, like set slot events - the bot will now
      predict a new action using the state before the most recent
      action."""
  
      type_name = "undo"
  
      def __hash__(self):
          return hash(32143124318)
  
      def __eq__(self, other):
          return isinstance(other, ActionReverted)
  
      def __str__(self):
          return "ActionReverted()"
  
      def as_story_string(self):
          return self.type_name
  
      def apply_to(self, tracker: 'DialogueStateTracker') -> None:
          tracker._reset()
          tracker.replay_events()
  
  
  # noinspection PyProtectedMember
  class StoryExported(Event):
      """Story should get dumped to a file."""
  
      type_name = "export"
  
      def __init__(self, path=None, timestamp=None):
          self.path = path
          super(StoryExported, self).__init__(timestamp)
  
      def __hash__(self):
          return hash(32143124319)
  
      def __eq__(self, other):
          return isinstance(other, StoryExported)
  
      def __str__(self):
          return "StoryExported()"
  
      def as_story_string(self):
          return self.type_name
  
      def apply_to(self, tracker: 'DialogueStateTracker') -> None:
          if self.path:
              tracker.export_stories_to_file(self.path)
  
  
  # noinspection PyProtectedMember
  class FollowupAction(Event):
      """Enqueue a followup action."""
  
      type_name = "followup"
  
      def __init__(self, name, timestamp=None):
          self.action_name = name
          super(FollowupAction, self).__init__(timestamp)
  
      def __hash__(self):
          return hash(self.action_name)
  
      def __eq__(self, other):
          if not isinstance(other, FollowupAction):
              return False
          else:
              return self.action_name == other.action_name
  
      def __str__(self):
          return "FollowupAction(action: {})".format(self.action_name)
  
      def as_story_string(self):
          props = json.dumps({"name": self.action_name})
          return "{name}{props}".format(name=self.type_name, props=props)
  
      @classmethod
      def _from_story_string(cls,
                             parameters: Dict[Text, Any]
                             ) -> Optional[List[Event]]:
  
          return [FollowupAction(parameters.get("name"),
                                 parameters.get("timestamp"))]
  
      def as_dict(self):
          d = super(FollowupAction, self).as_dict()
          d.update({"name": self.action_name})
          return d
  
      def apply_to(self, tracker: 'DialogueStateTracker') -> None:
          tracker.trigger_followup_action(self.action_name)
  
  
  # noinspection PyProtectedMember
  class ConversationPaused(Event):
      """Ignore messages from the user to let a human take over.
  
      As a side effect the ``Tracker``'s ``paused`` attribute will
      be set to ``True``. """
  
      type_name = "pause"
  
      def __hash__(self):
          return hash(32143124313)
  
      def __eq__(self, other):
          return isinstance(other, ConversationPaused)
  
      def __str__(self):
          return "ConversationPaused()"
  
      def as_story_string(self):
          return self.type_name
  
      def apply_to(self, tracker):
          tracker._paused = True
  
  
  # noinspection PyProtectedMember
  class ConversationResumed(Event):
      """Bot takes over conversation.
  
      Inverse of ``PauseConversation``. As a side effect the ``Tracker``'s
      ``paused`` attribute will be set to ``False``."""
  
      type_name = "resume"
  
      def __hash__(self):
          return hash(32143124314)
  
      def __eq__(self, other):
          return isinstance(other, ConversationResumed)
  
      def __str__(self):
          return "ConversationResumed()"
  
      def as_story_string(self):
          return self.type_name
  
      def apply_to(self, tracker):
          tracker._paused = False
  
  
  # noinspection PyProtectedMember
  class ActionExecuted(Event):
      """An operation describes an action taken + its result.
  
      It comprises an action and a list of events. operations will be appended
      to the latest ``Turn`` in the ``Tracker.turns``."""
  
      type_name = "action"
  
      def __init__(self,
                   action_name,
                   policy=None,
                   confidence=None,
                   timestamp=None):
          self.action_name = action_name
          self.policy = policy
          self.confidence = confidence
          self.unpredictable = False
          super(ActionExecuted, self).__init__(timestamp)
  
      def __str__(self):
          return ("ActionExecuted(action: {}, policy: {}, confidence: {})"
                  "".format(self.action_name, self.policy, self.confidence))
  
      def __hash__(self):
          return hash(self.action_name)
  
      def __eq__(self, other):
          if not isinstance(other, ActionExecuted):
              return False
          else:
              return self.action_name == other.action_name
  
      def as_story_string(self):
          return self.action_name
  
      @classmethod
      def _from_story_string(
          cls,
          parameters: Dict[Text, Any]
      ) -> Optional[List[Event]]:
  
          return [ActionExecuted(parameters.get("name"),
                                 parameters.get("policy"),
                                 parameters.get("confidence"),
                                 parameters.get("timestamp")
                                 )]
  
      def as_dict(self):
          d = super(ActionExecuted, self).as_dict()
          policy = None  # for backwards compatibility (persisted evemts)
          if hasattr(self, "policy"):
              policy = self.policy
          confidence = None
          if hasattr(self, "confidence"):
              confidence = self.confidence
  
          d.update({
              "name": self.action_name,
              "policy": policy,
              "confidence": confidence
          })
          return d
  
      def apply_to(self, tracker: 'DialogueStateTracker') -> None:
  
          tracker.set_latest_action_name(self.action_name)
          tracker.clear_followup_action()
  
  
  class AgentUttered(Event):
      """The agent has said something to the user.
  
      This class is not used in the story training as it is contained in the
      ``ActionExecuted`` class. An entry is made in the ``Tracker``."""
  
      type_name = "agent"
  
      def __init__(self, text=None, data=None, timestamp=None):
          self.text = text
          self.data = data
          super(AgentUttered, self).__init__(timestamp)
  
      def __hash__(self):
          return hash((self.text, jsonpickle.encode(self.data)))
  
      def __eq__(self, other):
          if not isinstance(other, AgentUttered):
              return False
          else:
              return (self.text, jsonpickle.encode(self.data)) == \
                     (other.text, jsonpickle.encode(other.data))
  
      def __str__(self):
          return "AgentUttered(text: {}, data: {})".format(
              self.text, json.dumps(self.data, indent=2))
  
      def apply_to(self, tracker: 'DialogueStateTracker') -> None:
  
          pass
  
      def as_story_string(self):
          return None
  
      def as_dict(self):
          d = super(AgentUttered, self).as_dict()
          d.update({
              "text": self.text,
              "data": self.data,
          })
          return d
  
      @staticmethod
      def empty():
          return AgentUttered()
  
      @classmethod
      def _from_parameters(cls, parameters):
          try:
              return AgentUttered(parameters.get("text"),
                                  parameters.get("data"),
                                  parameters.get("timestamp"))
          except KeyError as e:
              raise ValueError("Failed to parse agent uttered event. "
                               "{}".format(e))
  
  
  class Form(Event):
      """If `name` is not None: activates a form with `name`
          else deactivates active form
      """
      type_name = "form"
  
      def __init__(self, name, timestamp=None):
          self.name = name
          super(Form, self).__init__(timestamp)
  
      def __str__(self):
          return "Form({})".format(self.name)
  
      def __hash__(self):
          return hash(self.name)
  
      def __eq__(self, other):
          if not isinstance(other, Form):
              return False
          else:
              return self.name == other.name
  
      def as_story_string(self):
          props = json.dumps({"name": self.name})
          return "{name}{props}".format(name=self.type_name, props=props)
  
      @classmethod
      def _from_story_string(cls, parameters):
          """Called to convert a parsed story line into an event."""
          return [Form(parameters.get("name"),
                       parameters.get("timestamp"))]
  
      def as_dict(self):
          d = super(Form, self).as_dict()
          d.update({"name": self.name})
          return d
  
      def apply_to(self, tracker: 'DialogueStateTracker') -> None:
          tracker.change_form_to(self.name)
  
  
  class FormValidation(Event):
      """Event added by FormPolicy to notify form action
          whether or not to validate the user input"""
  
      type_name = "form_validation"
  
      def __init__(self,
                   validate,
                   timestamp=None):
          self.validate = validate
          super(FormValidation, self).__init__(timestamp)
  
      def __str__(self):
          return "FormValidation({})".format(self.validate)
  
      def __hash__(self):
          return hash(self.validate)
  
      def __eq__(self, other):
          return isinstance(other, FormValidation)
  
      def as_story_string(self):
          return None
  
      @classmethod
      def _from_parameters(cls, parameters):
          return FormValidation(parameters.get("validate"),
                                parameters.get("timestamp"))
  
      def as_dict(self):
          d = super(FormValidation, self).as_dict()
          d.update({"validate": self.validate})
          return d
  
      def apply_to(self, tracker: 'DialogueStateTracker') -> None:
          tracker.set_form_validation(self.validate)
  
  
  class ActionExecutionRejected(Event):
      """Notify Core that the execution of the action has been rejected"""
  
      type_name = 'action_execution_rejected'
  
      def __init__(self,
                   action_name,
                   policy=None,
                   confidence=None,
                   timestamp=None):
          self.action_name = action_name
          self.policy = policy
          self.confidence = confidence
          super(ActionExecutionRejected, self).__init__(timestamp)
  
      def __str__(self):
          return ("ActionExecutionRejected("
                  "action: {}, policy: {}, confidence: {})"
                  "".format(self.action_name, self.policy, self.confidence))
  
      def __hash__(self):
          return hash(self.action_name)
  
      def __eq__(self, other):
          if not isinstance(other, ActionExecutionRejected):
              return False
          else:
              return self.action_name == other.action_name
  
      @classmethod
      def _from_parameters(cls, parameters):
          return ActionExecutionRejected(parameters.get("name"),
                                         parameters.get("policy"),
                                         parameters.get("confidence"),
                                         parameters.get("timestamp"))
  
      def as_story_string(self):
          return None
  
      def as_dict(self):
          d = super(ActionExecutionRejected, self).as_dict()
          d.update({"name": self.action_name,
                    "policy": self.policy,
                    "confidence": self.confidence})
          return d
  
      def apply_to(self, tracker: 'DialogueStateTracker') -> None:
          tracker.reject_action(self.action_name)
  