conformance: NewType isn't a class

Author: KotlinIsland

conformance/tests/aliases_newtype.py

@@ -14,6 +14,8 @@
 
 assert_type(UserId(5) + 1, int)
 
+UserId.mro()  # E: NewType is not an instance of `type`
+
 # > Both isinstance and issubclass, as well as subclassing will fail for
 # > NewType('Derived', Base) since function objects don’t support these
 # > operations.