code: def median(self, **kwargs):
      return self.aggregate("median", **kwargs)
  
imports: from collections import OrderedDict
  from ....serialization.serializables import AnyField, Int64Field, BoolField, StringField, Int32Field
  from ....utils import pd_release_version
  from ...core import DATAFRAME_TYPE
  from ...utils import build_empty_df, build_empty_series, validate_axis
  from ..core import Window
label_desc: Use image node_id 18 for calling the Rolling obj's underlying member method code with example usage: obj.median() and returns: self