Determine whether this line is addressing us.

def check_for_interest(self, client, recipient, message):
        """Determine whether this line is addressing us."""
        for prefix in self.prefixes:
            if message.startswith(prefix):
                return True, message[len(prefix):]

        # Don't require a prefix if addressed in PM.
        # This comes after the prefix checks because
        # if the user does include a prefix, we want
        # to strip it, even in PM.
        if not isinstance(recipient, Channel):
            return True, message

        return False, None