code: def value_name(self):
      return self._value_name
  
imports: import numpy
  import pandas
  from ...None import opcodes
  from ...core import recursive_tile
  from ...serialization.serializables import AnyField, StringField
  from ...utils import calc_nsplits
  from ..operands import DataFrameOperand, DataFrameOperandMixin, OutputType
  from ..utils import build_empty_df, parse_index, standardize_range_index
label_desc: Use image node_id 5 for calling the DataFrameMelt obj's underlying member method code with example usage: obj.value_name() and returns: self