fix: pylint issues reported by ci

[E0606(possibly-used-before-assignment), TeamMixin.add_team_submission_context] Possibly using variable team_submission before assignment

[E0606(possibly-used-before-assignment), serialize_training_examples] Possibly using variable parts before assignment

[E0606(possibly-used-before-assignment), StaffWorkflowListViewUnitTests.test_bulk_fetch_annotated_staff_workflows] Possibly using variable assessment_ids before assignment

openassessment/staffgrader/tests/test_list_staff_workflows.py

@@ -564,6 +564,7 @@ def assert_annotated_staff_workflow_equal(self, expected, actual, i):
     @freeze_time(TEST_START_DATE)
     def test_bulk_fetch_annotated_staff_workflows(self, xblock, set_up_grades, set_up_locks):
         """ Unit test for bulk_fetch_annotated_staff_workflows """
+        assessment_ids = None
         if set_up_grades:
             # If we are grading, student_0 graded by staff_1, student_1 ungraded,
             #  student_2 graded by staff_0, student_3 by staff_1

openassessment/xblock/team_mixin.py

@@ -134,7 +134,7 @@ def add_team_submission_context(
             raise TypeError("One of team_submission_uuid or individual_submission_uuid must be provided")
         if team_submission_uuid:
             team_submission = get_team_submission(team_submission_uuid)
-        elif individual_submission_uuid:
+        else:
             team_submission = get_team_submission_from_individual_submission(individual_submission_uuid)
 
         team = self.teams_service.get_team_by_team_id(team_submission['team_id'])

openassessment/xblock/utils/xml.py

@@ -625,6 +625,7 @@ def serialize_training_examples(examples, assessment_el):
         answer_el = etree.SubElement(example_el, 'answer')
         try:
             answer = example_dict.get('answer')
+            parts = []
             if answer is None:
                 parts = []
             elif isinstance(answer, dict):