code: def __check_for_binary_feature(x):
      """
      Helper function to check if a feature column is binary.
      Checks if only the values true and false (or 0 and 1) are present in the values.
  
      :param y: the values to check for.
      :type y: pandas.Series or numpy.array
  
      :return: None
      :rtype: None
  
      :raises: ``ValueError`` if the values are not binary.
      """
      if not set(x) == {0, 1}:
          if len(set(x)) > 2:
              raise ValueError(
                  "[target_binary_feature_binary_test] Feature is not binary!"
              )
  
          warnings.warn(
              "A binary feature should have only "
              "values 1 and 0 (incl. True and False). "
              "Instead found "
              + str(set(x))
              + " in feature ''"
              + str(x.name)
              + "''.",
              RuntimeWarning,
          )
  
file_path: tsfresh/tsfresh/feature_selection/significance_tests.py
imports: import warnings
  from builtins import str
  import numpy
  import pandas
  from scipy import stats
label_desc: Use image node_id 7 for calling a global function with example usage: __check_for_binary_feature(x) without return types