def neutralize_variable(self, variable_name):
        """
        Neutralizes an OpenFisca variable existing in the tax and benefit system.

        A neutralized variable always returns its default value when computed.

        Trying to set inputs for a neutralized variable has no effect except raising a warning.
        """
        self.variables[variable_name] = get_neutralized_variable(self.get_variable(variable_name))