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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_expect_string_healthcheck(self, expect_string):
 """Inserts a new healthckeck_expect with only expect_string. :param expect_string: expect_string. :return: Dictionary with the following structure: :: {'healthcheck_expect': {'id': < id >}} :raise InvalidParameterError: The value of expect_string is invalid. :raise HealthCheckExpectJaCadastradoError: There is already a healthcheck_expect registered with the same data. :raise HealthCheckExpectNaoExisteError: Healthcheck_expect not registered. :raise DataBaseError: Networkapi failed to access the database. :raise XMLError: Networkapi failed to generate the XML response. """


        healthcheck_map = dict()
        healthcheck_map['expect_string'] = expect_string

        url = 'healthcheckexpect/add/expect_string/'

        code, xml = self.submit({'healthcheck': healthcheck_map}, 'POST', url)

        return self.response(code, xml)