code: def raise_for_response(self, responses):
          
          exception_messages = [self.client.format_exception_message(response) for response in responses]
          if len(exception_messages) == 1:
              message = exception_messages[0]
          else:
              message = "[%s]" % ", ".join(exception_messages)
          raise PostmarkerException(message)
docs: Constructs appropriate exception from list of responses and raises it.