docs: def clear_choice(self, choice):
          """stub"""
          if len(self.my_osid_object_form._my_map['choices']) == 0:
              raise IllegalState('there are currently no choices defined for this question')
          if (len(self.my_osid_object_form._my_map['choices']) == 1 and
                  choice in self.my_osid_object_form._my_map['choices']):
              raise IllegalState()
          self.my_osid_object_form._my_map['choices'] = \
              [c for c in self.my_osid_object_form._my_map['choices'] if c != choice]