code: def iter(self, keys):
      for key, item in self.TIME_TRANSFOMERS.items():
          if key in keys:
              yield key, item
  
imports: from itertools import combinations
  import warnings
  import numpy
  from scipy import stats
  import pandas
  from lifelines import utils
  from lifelines.utils import group_survival_table_from_events, string_rjustify, format_p_value, format_floats, interpolate_at_times_and_return_pandas, _expected_value_of_survival_up_to_t, _expected_value_of_survival_squared_up_to_t
  from lifelines import KaplanMeierFitter
label_desc: Use image node_id 2 for calling the TimeTransformers obj's underlying member method code with example usage: obj.iter(keys) without return types