diff --git a/aws-dynamodb-encryption-python-master/src/dynamodb_encryption_sdk/structures.py b/aws-dynamodb-encryption-python-master/src/dynamodb_encryption_sdk/structures.py
index 61b329c..2dfaac2 100644
--- a/aws-dynamodb-encryption-python-master/src/dynamodb_encryption_sdk/structures.py
+++ b/aws-dynamodb-encryption-python-master/src/dynamodb_encryption_sdk/structures.py
@@ -183,7 +183,7 @@ def set_index_keys(self, *keys):
         for key in keys:
             index_action = min(self.action(key), CryptoAction.SIGN_ONLY)
             try:
-                if self.attribute_actions[key] is not index_action:
+                if self.attribute_actions[key] != index_action:
                     raise InvalidArgumentError(
                         'Cannot overwrite a previously requested action on indexed attribute: "{}"'.format(key)
                     )