content: # Copyright 2015 Spotify AB. All rights reserved.
  #
  # The contents of this file are licensed under the Apache License, Version 2.0
  # (the "License"); you may not use this file except in compliance with the
  # License. You may obtain a copy of the License at
  #
  # http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  # License for the specific language governing permissions and limitations under
  # the License.
  
  """napalm.base package."""
  
  # Python std lib
  import inspect
  import importlib
  
  # NAPALM base
  from typing import Type
  
  from napalm.base.base import NetworkDriver
  from napalm.base.exceptions import ModuleImportError
  from napalm.base.mock import MockDriver
  
  __all__ = [
      "get_network_driver",  # export the function
      "NetworkDriver",  # also export the base class
  ]
  
  
  def get_network_driver(name: str, prepend: bool = True) -> Type[NetworkDriver]:
      """
      Searches for a class derived form the base NAPALM class NetworkDriver in a specific library.
      The library name must repect the following pattern: napalm_[DEVICE_OS].
      NAPALM community supports a list of devices and provides the corresponding libraries; for
      full reference please refer to the `Supported Network Operation Systems`_ paragraph on
      `Read the Docs`_.
  
      .. _`Supported Network Operation Systems`: \
      http://napalm.readthedocs.io/en/latest/#supported-network-operating-systems
      .. _`Read the Docs`: \
      http://napalm.readthedocs.io/
  
      :param name:         the name of the device operating system or the name of the library.
      :return:                    the first class derived from NetworkDriver, found in the library.
      :raise ModuleImportError:   when the library is not installed or a derived class from \
      NetworkDriver was not found.
  
      Example::
  
      .. code-block:: python
  
          >>> get_network_driver('junos')
          <class 'napalm.junos.junos.JunOSDriver'>
          >>> get_network_driver('IOS-XR')
          <class 'napalm.iosxr.iosxr.IOSXRDriver'>
          >>> get_network_driver('napalm.eos')
          <class 'napalm.eos.eos.EOSDriver'>
          >>> get_network_driver('wrong')
          napalm.base.exceptions.ModuleImportError: Cannot import "napalm_wrong". Is the library \
          installed?
      """
      if name == "mock":
          return MockDriver
  
      if not (isinstance(name, str) and len(name) > 0):
          raise ModuleImportError("Please provide a valid driver name.")
  
      # Only lowercase allowed
      name = name.lower()
      # Try to not raise error when users requests IOS-XR for e.g.
      module_install_name = name.replace("-", "")
      community_install_name = "napalm_{name}".format(name=module_install_name)
      custom_install_name = "custom_napalm.{name}".format(name=module_install_name)
      # Can also request using napalm_[SOMETHING]
      if "napalm" not in module_install_name and prepend is True:
          module_install_name = "napalm.{name}".format(name=module_install_name)
      # Order is custom_napalm_os (local only) ->  napalm.os (core) ->  napalm_os (community)
      for module_name in [
          custom_install_name,
          module_install_name,
          community_install_name,
      ]:
          try:
              module = importlib.import_module(module_name)
              break
          except ImportError as e:
              message = str(e)
              if "No module named" in message:
                  # py2 doesn't have ModuleNotFoundError exception
                  failed_module = message.split()[-1]
                  if failed_module.replace("'", "") in module_name:
                      continue
              raise e
      else:
          raise ModuleImportError(
              'Cannot import "{install_name}". Is the library installed?'.format(
                  install_name=name
              )
          )
  
      for name, obj in inspect.getmembers(module):
          if inspect.isclass(obj) and issubclass(obj, NetworkDriver):
              return obj
  
      # looks like you don't have any Driver class in your module...
      raise ModuleImportError(
          'No class inheriting "napalm.base.base.NetworkDriver" found in "{install_name}".'.format(
              install_name=module_install_name
          )
      )
  