content: # Apache Software License 2.0
  #
  # Copyright (c) ZenML GmbH 2025. All rights reserved.
  #
  # 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.
  #
  
  
  from typing import Union
  
  import pandas as pd
  
  
  class NADropper:
      """Support class to drop NA values in sklearn Pipeline."""
  
      def fit(self, *args, **kwargs):
          return self
  
      def transform(self, X: Union[pd.DataFrame, pd.Series]):
          return X.dropna()
  
  
  class ColumnsDropper:
      """Support class to drop specific columns in sklearn Pipeline."""
  
      def __init__(self, columns):
          self.columns = columns
  
      def fit(self, *args, **kwargs):
          return self
  
      def transform(self, X: Union[pd.DataFrame, pd.Series]):
          return X.drop(columns=self.columns)
  
  
  class DataFrameCaster:
      """Support class to cast type back to pd.DataFrame in sklearn Pipeline."""
  
      def __init__(self, columns):
          self.columns = columns
  
      def fit(self, *args, **kwargs):
          return self
  
      def transform(self, X):
          return pd.DataFrame(X, columns=self.columns)
  