code: def __len__(self):
      return sum(
          grouped_df.ngroups
          for grouped_df in self.grouped_dict.values()
      )
  
imports: import itertools
  from collections import defaultdict, namedtuple
  from typing import Iterable, Sized
  import pandas
label_desc: Use image node_id 3 for calling the TsDictAdapter obj's underlying member method code with example usage: obj.__len__() and returns: sum