diff --git a/es_index.py b/es_index.py
index 83fb15e..8866904 100644
--- a/es_index.py
+++ b/es_index.py
@@ -38,6 +38,9 @@ class ESIndex(PyOperator):
     def __call__(self, doc: Union[dict, List[dict]]):
         if isinstance(doc, dict):
             docs = [doc]
+        else:
+            docs = doc
+
         for x in docs:
             assert isinstance(x, dict)