<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def alterar(self, id_script, id_script_type, script, description, model=None):
 """Change Script from by the identifier. :param id_script: Identifier of the Script. Integer value and greater than zero. :param id_script_type: Identifier of the Script Type. Integer value and greater than zero. :param script: Script name. String with a minimum 3 and maximum of 40 characters :param description: Script description. String with a minimum 3 and maximum of 100 characters :return: None :raise InvalidParameterError: The identifier of Script, script Type, script or description is null and invalid. :raise RoteiroNaoExisteError: Script not registered. :raise TipoRoteiroNaoExisteError: Script Type not registered. :raise NomeRoteiroDuplicadoError: Script already registered with informed. :raise DataBaseError: Networkapi failed to access the database. :raise XMLError: Networkapi failed to generate the XML response. """

        if not is_valid_int_param(id_script):
            raise InvalidParameterError(u'The identifier of Script is invalid or was not informed.')

        script_map = dict()
        script_map['id_script_type'] = id_script_type
        script_map['script'] = script
        script_map['model'] = model
        script_map['description'] = description

        url = 'script/edit/' + str(id_script) + '/'

        code, xml = self.submit({'script': script_map}, 'PUT', url)

        return self.response(code, xml)