code: def neutralize_variable(self, variable_name):
          
          self.variables[variable_name] = get_neutralized_variable(self.get_variable(variable_name))
docs: 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.