code: def __len__(self):
      return self.df_grouped.ngroups * len(self.value_columns)
  
imports: import itertools
  from collections import defaultdict, namedtuple
  from typing import Iterable, Sized
  import pandas
label_desc: Use image node_id 2 for calling the WideTsFrameAdapter obj's underlying member method code with example usage: obj.__len__() and returns: unknown