code: def test_flatten_on_json_is_noop(obj):
      assert flatten(obj) == obj
  
file_path: sacred/tests/test_serializer.py
imports: import pytest
  from sacred.serializer import flatten, restore
  import sacred.optional
label_desc: Use image node_id 1 for calling a global function with example usage: test_flatten_on_json_is_noop(obj) without return types