diff --git a/py34/bacpypes/primitivedata.py b/py34/bacpypes/primitivedata.py
index 57f842e..c1c5c9a 100755
--- a/py34/bacpypes/primitivedata.py
+++ b/py34/bacpypes/primitivedata.py
@@ -1255,6 +1255,7 @@ class Enumerated(Atomic):
         """Return True if arg is valid value for the class.  If the string
         value is wrong for the enumeration, the encoding will fail.
         """
+        cls(arg)
         return (isinstance(arg, int) and (arg >= 0)) or \
             isinstance(arg, str)