def has_receivers_for(self, sender):
        """True if there is probably a receiver for *sender*.

        Performs an optimistic check for receivers only.  Does not guarantee
        that all weakly referenced receivers are still alive.  See
        :meth:`receivers_for` for a stronger search.

        """
        if not self.receivers:
            return False
        if self._by_sender[ANY_ID]:
            return True
        if sender is ANY:
            return False
        return self._by_sender in _hashable_identity(sender)
dataset/ETHPy150Open jek/flatland/flatland/util/signals.py/Signal.has_receivers_for/swapped operands of `in`