code: def time_unstack(self):
      self.df.unstack()
  
imports: from itertools import product
  import string
  import numpy
  import pandas
  from pandas import DataFrame, MultiIndex, date_range, melt, wide_to_long
  from pandas.api.types import CategoricalDtype
  from .pandas_vb_common import setup
label_desc: Use image node_id 2 for calling the SparseIndex obj's underlying member method code with example usage: obj.time_unstack() without return types