diff --git a/git_json_tree.py b/git_json_tree.py
index e241d6e..42505c7 100644
--- a/git_json_tree.py
+++ b/git_json_tree.py
@@ -56,7 +56,6 @@ def _from_obj(obj):
                 yield path + ['.object'], None
 
             for key, value in item.items():
-                assert isinstance(key, str)
                 stack.insert(0, (path + [json.dumps(key)], value))
         elif isinstance(item, (tuple, list)):
             if not item:
diff --git a/test_git_json_tree.py b/test_git_json_tree.py
index 45cc4e9..4aba628 100644
--- a/test_git_json_tree.py
+++ b/test_git_json_tree.py
@@ -37,7 +37,7 @@ def json_data():
 
 
 @given(data=json_data())
-@settings(max_examples=1000, deadline=500)
+@settings(max_examples=1000, deadline=10000)
 def test_encode_decode(data, repo):
     """Test (d)encoding."""
     assume(isinstance(data, (dict, list)))