Merge pull request #268 from vbnmmnbv/activate_pie

fix activate uid none check

kmip/pie/client.py

@@ -506,7 +506,7 @@ class ProxyKmipClient(api.KmipClient):
             message = result.result_message.value
             raise exceptions.KmipOperationFailure(status, reason, message)
 
-    def activate(self, uid):
+    def activate(self, uid=None):
         """
         Activate a managed object stored by a KMIP appliance.
 
@@ -522,6 +522,7 @@ class ProxyKmipClient(api.KmipClient):
             TypeError: if the input argument is invalid
         """
         # Check input
+        if uid is not None:
             if not isinstance(uid, six.string_types):
                 raise TypeError("uid must be a string")