OSIS-4502 extract method
OSIS-4502 extract method

	modified:   base/models/group_element_year.py

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