OSIS-2670 Optimized imports
OSIS-2670 Optimized imports

	modified:   base/tests/forms/test_validation_rule_mixin.py

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