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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def wait_travel(self, character, thing, dest, cb=None):
 """Schedule a thing to travel someplace, then wait for it to finish, and call ``cb`` if provided :param character: name of the character :param thing: name of the thing :param dest: name of the destination (a place) :param cb: function to be called when I'm done :return: ``None`` """

        self.wait_turns(self.engine.character[character].thing[thing].travel_to(dest), cb=cb)