OSIS-2169 Explain code
OSIS-2169 Explain code

	modified:   base/business/group_element_years/management.py

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