diff --git a/5-pg-field-type-detector.py b/5-pg-field-type-detector.py
index a3f065a8ecb2fc1218b8c47818877bc863d3c70e..a7f9859881ccb5abfc2c734585067cdda6419ead 100644
--- a/5-pg-field-type-detector.py
+++ b/5-pg-field-type-detector.py
@@ -188,7 +188,7 @@ def generate_field_catalog( cfg, catalog=None ):
         logging.info('Done.')
         #field_catalog = generate_field_catalog( cfg, pg_connection, field_catalog )
 
-        if 'whitelist' in cfg['postgis']['databases'][dbname].keys():
+        if isinstance()'whitelist' in cfg['postgis']['databases'][dbname], dict) and 'whitelist' in cfg['postgis']['databases'][dbname].keys():
             whitelist = cfg['postgis']['databases'][dbname]['whitelist']
         else:
             whitelist = None