def subscribe_to_read(self, address_range, callback):
        for address in address_range:
            address &= self.physMask
            callbacks = self._read_subscribers.setdefault(address, [])
            if callbacks not in callback:
                callbacks.append(callback)
dataset/ETHPy150Open mnaberez/py65/py65/memory.py/ObservableMemory.subscribe_to_read/swapped operands of `not in`