OSIS-1750 Correct call isinstance in xls_comparaison
OSIS-1750 Correct call isinstance in xls_comparaison

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