def receiveMessage(self, msg, sender):
        if msg == 'Best Friend':
            if not self.bestFriend:
                self.bestFriend = self.createActor(Lassie)
            self.send(self.bestFriend, msg)
            return

        if msg == 'Best Friend Says':
            if not self.bestFriend:
                self.send(sender, 'no best friend')
            else:
                self.waiter = sender
                self.send(self.bestFriend, 'what')
        elif self.bestFriend and self.bestFriend == sender:
            if self.waiter:
                if sender is not self.bestFriend:
                    self.send(self.waiter, "ERROR: lcl/rmt address comparison not epimorphic.")
                else:
                    self.send(self.waiter, msg)
                self.waiter = None
            else:
                pass # discard message from bestFriend; normal for this test
        else:
            if sender != self.myAddress:
                self.send(sender, 'Greetings.')
dataset/ETHPy150Open godaddy/Thespian/thespian/test/testMultipleActorSystems.py/ActorsLikeDogs.receiveMessage/operator `!=` -> `is not`