def get_peer_resources(self, peer_jid):
        """
        Return a dict mapping resources of the given bare `peer_jid` to the
        presence state last received for that resource.

        Unavailable presence states are not included. If the bare JID is in a
        error state (i.e. an error presence stanza has been received), the
        returned mapping is empty.
        """
        try:
            d = dict(self._presences[peer_jid])
            d.pop(None, None)
            return d
        except KeyError:
            return {}