Add a new trigger
        :param response: The Response object
        :type  response: Response or Condition

        :param weight: The weight of the response
        :type  weight: int

def _add_response(self, response, weight=1):
        """
        Add a new trigger
        :param response: The Response object
        :type  response: Response or Condition

        :param weight: The weight of the response
        :type  weight: int
        """
        # If no response with this priority level has been defined yet, create a new list
        if response.priority not in self._responses:
            self._responses[response.priority] = [(response, weight)]
            return

        # Otherwise, add this trigger to an existing priority list
        self._responses[response.priority].append((response, weight))