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Alyssa is a student, and she can view assignments and submit her solutions. She can download the assignment files, upload a submission, and view her own grades as well as the class grade histogram. For coding assignments, each submission is graded automatically using the test script. If the tests fail, then an explanation and a stack trace would be shown.
The TA can grant an extension to the student simply by changing the due date for the problem set. In this sketch, an extension was granted to Louis by rcm. In addition, the TA can look at each student's score and submission summary.