class_docstr: DataSource which loads data from a pandas DataFrame.
  
  Inputs:
      train_df: DataFrame for training
  
      eval_df: DataFrame for evalu
  
      test_df: DataFrame for test
  
      schema: same as base DataSource, define the list of output values with their types
  
      column_mapping: maps the column names in DataFrame to the name defined in schema
code: def __init__(
      self,
      train_df: Optional[DataFrame] = None,
      eval_df: Optional[DataFrame] = None,
      test_df: Optional[DataFrame] = None,
      **kwargs,
  ):
      super().__init__(**kwargs)
      self.train_df = train_df
      self.eval_df = eval_df
      self.test_df = test_df
  
file_path: pytext/pytext/data/sources/pandas.py
imports: from typing import Dict, Optional, Type
  from pandas import DataFrame
  from pytext.data.sources.data_source import RootDataSource
  from .session import SessionDataSource
label_desc: Use image node_id 2 to create a new PandasDataSource object from inherited base classes: RootDataSource with example: obj = PandasDataSource(train_df, eval_df, test_df)