take the list of users for enrolment change

common/djangoapps/student/management/commands/change_enrollment.py

@@ -70,10 +70,12 @@ class Command(BaseCommand):
             mode=options['from_mode']
         )
         if options['user']:
-            if '@' in options['user']:
-                user = User.objects.get(email=options['user'])
+            user_str = options['user']
+            for username in user_str.split(","):
+                if '@' in username:
+                    user = User.objects.get(email=username)
                 else:
-                user = User.objects.get(username=options['user'])
+                    user = User.objects.get(username=username)
                 filter_args['user'] = user
                 enrollments = CourseEnrollment.objects.filter(**filter_args)
                 if options['noop']: