code: def _check_emotion_set_is_supported(self):
          
          supported_emotion_subsets = [
              set(['anger', 'fear', 'surprise', 'calm']),
              set(['happiness', 'disgust', 'surprise']),
              set(['anger', 'fear', 'surprise']),
              set(['anger', 'fear', 'calm']),
              set(['anger', 'happiness', 'calm']),
              set(['anger', 'fear', 'disgust']),
              set(['calm', 'disgust', 'surprise']),
              set(['sadness', 'disgust', 'surprise']),
              set(['anger', 'happiness'])
          ]
          if not set(self.target_emotions) in supported_emotion_subsets:
              error_string = 'Target emotions must be a supported subset. '
              error_string += 'Choose from one of the following emotion subset: \n'
              possible_subset_string = ''
              for emotion_set in supported_emotion_subsets:
                  possible_subset_string += ', '.join(emotion_set)
                  possible_subset_string += '\n'
              error_string += possible_subset_string
              raise ValueError(error_string)
docs: Validates set of user-supplied target emotions.