diff --git a/ippisite/ippidb/management/commands/import_v1_data.py b/ippisite/ippidb/management/commands/import_v1_data.py
index 69948d26554c89e2545dd9f22523133075f2fc94..4386708e747abb5a8aa46f40d5c90dcbd0a70683 100644
--- a/ippisite/ippidb/management/commands/import_v1_data.py
+++ b/ippisite/ippidb/management/commands/import_v1_data.py
@@ -171,7 +171,7 @@ select distinct protein.NumUniprot, domain.PfamNumAccession  , complexe.NbCopy,
                     else:
                         ppi = Ppi.objects.get(id=ppi_ids_mapping[row[6]])
                     # create a complex
-                    if row[3]=="null":
+                    if row[3] is None:
                         c = ProteinDomainPartnerComplex()
                     else:
                         c = ProteinDomainBoundComplex()