<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def status(self, external_id, **params):
 """ Retrieves the verification result for an App Verify transaction by external_id. To ensure a secure verification flow you must check the status using TeleSign's servers on your backend. Do not rely on the SDK alone to indicate a successful verification. See https://developer.telesign.com/docs/app-verify-android-sdk-self#section-get-status-service or https://developer.telesign.com/docs/app-verify-ios-sdk-self#section-get-status-service for detailed API documentation. """

        return self.get(APPVERIFY_STATUS_RESOURCE.format(external_id=external_id),
                        **params)