fixup! feat(firestore): *DocumentReference: add types

Author: tharvik

packages/google-cloud-firestore/google/cloud/firestore_v1/base_document.py

@@ -392,7 +392,7 @@ def _prep_batch_get(
             mask = None
 
         if self._client is None:
-            raise ValueError("A batch requires a `client`.")
+            raise ValueError("A get requires a `client`.")
         request = {
             "database": self._client._database_string,
             "documents": [self._document_path],