fix(lottery): cast priority index to int in get_computed_schedule (learning-unlimited#4768)

* fix(lottery): cast priority index to int in get_computed_schedule fixes learning-unlimited#4759

* fix(lottery): use raw string for regex in get_computed_schedule fixes learning-unlimited#4759

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Co-authored-by: hwatheod <ted@learningu.org>

Author: prem-2006

esp/esp/program/controllers/lottery.py

@@ -690,9 +690,9 @@ def get_computed_schedule(self, student_id, mode='assigned'):
             assignments = numpy.nonzero(self.priority[1][self.student_indices[student_id],:])[0]
         else:
             import re
-            p = re.search('(?<=priority_)\d*', mode).group(0)
+            p = re.search(r'(?<=priority_)\d*', mode).group(0)
             if p:
-                assignments = numpy.nonzero(self.priority[p][self.student_indices[student_id],:])[0]
+                assignments = numpy.nonzero(self.priority[int(p)][self.student_indices[student_id],:])[0]
         result = []
         for i in range(assignments.shape[0]):
             result.append(ClassSection.objects.get(id=self.section_ids[assignments[i]]))