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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 PostUnregistration(method):
 # pylint: disable=C0103 """ The service post-unregistration callback decorator is called after a service of the component has been unregistered from the framework. The decorated method must accept the :class:`~pelix.framework.ServiceReference` of the registered service as argument:: @PostUnregistration def callback_method(self, service_reference):
 ''' service_reference: The ServiceReference of the provided service ''' :param method: The decorated method :raise TypeError: The decorated element is not a valid function """

    if not isinstance(method, types.FunctionType):
        raise TypeError("@PostUnregistration can only be applied on functions")

    # Tests the number of parameters
    validate_method_arity(method, "service_reference")
    _append_object_entry(
        method,
        constants.IPOPO_METHOD_CALLBACKS,
        constants.IPOPO_CALLBACK_POST_UNREGISTRATION,
    )
    return method