docs: def summary(self, scoring):
          """
          Prints out the summary of validation for giving scoring function.
          """
  
          if scoring == 'class_confusion':
              print('*' * 50)
              print('  Confusion Matrix ')
              print('x-axis: ' + ' | '.join(list(self.class_dictionary.keys())))
              print('y-axis: ' + ' | '.join(self.truth_classes))
              print(self.confusion_matrix())