code: def bias(self):
      return self._bias
  
file_path: mars/mars/dataframe/reduction/skew.py
imports: import numpy
  from ...None import opcodes
  from ...config import options
  from ...core import OutputType, ENTITY_TYPE
  from ...serialization.serializables import BoolField
  from .core import DataFrameReductionOperand, DataFrameReductionMixin
label_desc: Use image node_id 2 for calling the DataFrameSkew obj's underlying member method code with example usage: obj.bias() and returns: self