code: def input(self):
      return self._input
  
imports: import numpy
  import pandas
  from ...None import opcodes
  from ...core import recursive_tile, get_output_types, ENTITY_TYPE, CHUNK_TYPE
  from ...core.custom_log import redirect_custom_log
  from ...serialization.serializables import KeyField, FunctionField, TupleField, DictField, BoolField, StringField, AnyField
  from ...utils import enter_current_session, has_unknown_shape, quiet_stdio, find_objects, replace_objects
  from ..operands import DataFrameOperand, DataFrameOperandMixin, OutputType
  from ..utils import build_df, build_empty_df, build_series, parse_index, validate_output_types, build_empty_series, clean_up_func, restore_func
label_desc: Use image node_id 2 for calling the DataFrameMapChunk obj's underlying member method code with example usage: obj.input() and returns: self