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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 add_function(self, function):
 """ Registers the function to the server's default fixed function manager. """

        #noinspection PyTypeChecker
        if not len(self.settings.FUNCTION_MANAGERS):
            raise ConfigurationError(
                'Where have the default function manager gone?!')
        self.settings.FUNCTION_MANAGERS[0].add_function(function)