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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 connect(self, callback: Callable[[T_Event], Any]) -> Callable[[T_Event], Any]: """ Connect a callback to this signal. Each callable can only be connected once. Duplicate registrations are ignored. If you need to pass extra arguments to the callback, you can use :func:`functools.partial` to wrap the callable. :param callback: a callable that will receive an event object as its only argument. :return: the value of ``callback`` argument """

        assert check_argument_types()
        if self.listeners is None:
            self.listeners = []
        if callback not in self.listeners:
            self.listeners.append(callback)

        return callback