Problem
1. Write a predicate to check whether a particular student met all the relevant requirements. That is, check whether a student did all the homework, and if a graduate student, whether the student wrote a thesis.
2. Add a class to the system to represent students taking the course for pass/fail credit. Assume that such students need not do the homework, but might do so. If they do, the homework should participate in determining whether they passed or failed, according to the normal formula. If they did no homework, then the grade is the average of their midterm and final grades. A passing grade is 60 or higher.