code: def add_state_group(self, name, *states):
          
          # See `_add_state_internal` for explanation of the following
          if hasattr(self, name):
              raise AttributeError(
                  "State group name %s conflicts with existing attribute in the state manager" % name)
          mstate = ManagedStateGroup(name, self, states)
          self.states[name] = mstate
          setattr(self, name, mstate)
          setattr(self, 'is_' + name.lower(), mstate)
docs: Add a group of managed states. Groups can be specified directly in the
          :class:`~coaster.utils.classes.LabeledEnum`. This method is only useful
          for grouping a conditional state with existing states. It cannot be
          used to form a group of groups.
  
          :param str name: Name of this group
          :param states: :class:`ManagedState` instances to be grouped together