code: def __iter__(self):
      for group_key, group in self.df_grouped:
          if self.column_sort is not None:
              group = group.sort_values(self.column_sort)
          yield Timeseries(
              group_key[0], str(group_key[1]), group[self.column_value]
          )
  
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 LongTsFrameAdapter obj's underlying member method code with example usage: obj.__iter__() without return types