How to post the json response of staff graded assignment data for lms

I wanted to use post api http://localhost:18000/courses/{course-key}/xblock/{usage-key}/handler/upload_assignment. but I did not understand from where to get usage-key for staff graded assignment.

@Richa_Tiwari the XBlock usage key is visible when browsing courses as staff. There’s a “Staff Debug Info” under each XBlock which opens a dialog showing the usage key under “location”.