def detect_event_conflict!(event_name, method_name = event_name)
      if method_already_implemented?(method_name)
        raise FiniteMachine::AlreadyDefinedError, EVENT_CONFLICT_MESSAGE % {
          name: event_name,
          type: :instance,
          method: method_name,
          source: 'FiniteMachine'
        }
      end
    end
def detect_event_conflict!(event_name, method_name = event_name)
      if method_already_implemented?(method_name)
        raise FiniteMachine::AlreadyDefinedError, EVENT_CONFLICT_MESSAGE % {
          name: event_name,
          type: :instance,
          method: method_name,
          source: 'FiniteMachine'
        }
      end
    end
Raise error when the method is already defined

 @example
   detect_event_conflict!(:test, "test=")

 @raise [FiniteMachine::AlreadyDefinedError]

 @return [nil]

 @api public