def send(self, sender, **named):
        """
        Send signal from sender to all connected receivers.

        If any receiver raises an error, the error propagates back through send,
        terminating the dispatch loop, so it is quite possible to not have all
        receivers called if a raises an error.

        Arguments:

            sender
                The sender of the signal Either a specific object or None.

            named
                Named arguments which will be passed to receivers.

        Returns a list of tuple pairs [(receiver, response), ... ].
        """
        responses = []
        if not self.receivers:
            return responses

        for receiver in self._live_receivers(_make_id(sender)):
            response = receiver(signal=self, sender=sender, **named)
            responses.append((receiver, response))
        return responses