Solution as below

To request a service ticket using the APIC-EM REST API, the following Python script can be used:
* Import necessary libraries (requests and json).
* Define the APIC-EM controller's URL.
* Create the payload with the username and password.
* Set the header to specify the content type as JSON.
* Make a POST request to the /api/v1/ticket endpoint with the payload and header.
* Parse the JSON response to extract the service ticket.
References:
* Cisco DevNet Associate Exam Topics: APIs and Automation (understanding how to use REST APIs)
* APIC-EM API Documentation (provides details on endpoints and request structures)