docs: def PostRegistration(method):
      # pylint: disable=C0103
      """
      The service post-registration callback decorator is called after a service
      of the component has been registered to the framework.
  
      The decorated method must accept the
      :class:`~pelix.framework.ServiceReference` of the registered
      service as argument::
  
         @PostRegistration
         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("@PostRegistration 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_REGISTRATION,
      )
      return method