code: def _contains(df, substr):
      return (
          [] if not substr else [c for c in df.columns if substr in c]
      )
  
imports: from copy import copy, deepcopy
  import abc
  import inspect
  import importlib
  import itertools
  from collections.abc import Mapping
  import pandas
  from decorator import decorator
  from sklearn_evaluation.exceptions import DataSelectorError
  from sklearn_evaluation.util import map_parameters_in_fn_call
  from sklearn_evaluation.table import Table
label_desc: Use image node_id 7 for calling a global function with example usage: _contains(df, substr) and returns: unknown