OSIS-1068 Added missing import
OSIS-1068 Added missing import

	modified:   assessments/tests/views/test_upload_xls_utils.py

uclouvain/OSIS-Louvain,uclouvain/osis_louvain,uclouvain/osis_louvain,uclouvain/osis,uclouvain/OSIS-Louvain,uclouvain/OSIS-Louvain,uclouvain/osis,uclouvain/osis,uclouvain/osis,uclouvain/osis_louvain