Bugfixes with blacklist and graylist

- There was a bug involving students with blacklists make requests
- is_blacklist_compatible & is_graylist_compatible always returned true

api/composite_user.py

@@ -97,7 +97,7 @@ class CompositeUser:
         your_past_partners: Set[str] = set()
         for assignment in self.graylist:
             if isinstance(self.graylist[assignment], set):
-                my_past_partners.union(self.graylist[assignment])
+                my_past_partners.update(self.graylist[assignment])
             elif isinstance(self.graylist[assignment], str):
                 my_past_partners.add(str(self.graylist[assignment]))
             else:
@@ -105,7 +105,7 @@ class CompositeUser:
                       f'are recorded as a {self.graylist[assignment].__class__}')
         for assignment in other.graylist:
             if isinstance(other.graylist[assignment], set):
-                your_past_partners.union(other.graylist[assignment])
+                your_past_partners.update(other.graylist[assignment])
             elif isinstance(other.graylist[assignment], str):
                 your_past_partners.add(str(other.graylist[assignment]))
             else:

prep_assignment.py

@@ -140,9 +140,9 @@ def create_pairs(students: Set[CompositeUser], groupset_name: str = 'Unknown Ass
         print('Next we shall assign partners to students with blacklists.')
     else:
         print('There are no students with blacklists.')
-    for student in students_with_blacklist:     # TODO: there's a bug here when students with blacklists make requests
+    for student in students_with_blacklist:
+        if student in unassigned_students:
             pair_number += 1
-        if student in unassigned_students:      # TODO: can probably fix bug by putting ALL the code under this "if"
             unassigned_students.remove(student)
             potential_partner: CompositeUser = random.choice(tuple(unassigned_students))
             while not (student.is_blacklist_compatible(potential_partner) and