Calculates the display name for a room.

def display_name(self):
        """Calculates the display name for a room."""
        if self.name:
            return self.name
        elif self.canonical_alias:
            return self.canonical_alias

        # Member display names without me
        members = [u.get_display_name(self) for u in self.get_joined_members() if
                   self.client.user_id != u.user_id]
        members.sort()

        if len(members) == 1:
            return members[0]
        elif len(members) == 2:
            return "{0} and {1}".format(members[0], members[1])
        elif len(members) > 2:
            return "{0} and {1} others".format(members[0], len(members) - 1)
        else:  # len(members) <= 0 or not an integer
            # TODO i18n
            return "Empty room"