--- a/xmlclass/xmlclass.py	Thu Aug 17 09:55:39 2017 +0300
+++ b/xmlclass/xmlclass.py	Thu Aug 17 10:04:24 2017 +0300
@@ -598,7 +598,7 @@
         "extract": ExtractTag,
         "generate": GenerateTag,
         "initial": lambda: None,
-        "check": lambda x: x is None or infos["minOccurs"] == 0 and value == True
+        "check": lambda x: x is None or infos["minOccurs"] == 0 and value
     }