def register(transition)
      event_type = transition.class.instance_variable_get(:@event_type)
      event_trigger_value = transition.event_trigger_value

      transition_map[event_type] ||= {}

      transitions =
        (transition_map[event_type][event_trigger_value] ||= [])
      transitions << transition

      transition
    end
def register(transition)
      event_type = transition.class.instance_variable_get(:@event_type)
      event_trigger_value = transition.event_trigger_value

      transition_map[event_type] ||= {}

      transitions =
        (transition_map[event_type][event_trigger_value] ||= [])
      transitions << transition

      transition
    end
@api private
 Registers a transition in the transition map.

 @param [Transition] transition the transition to register.