code: def test_serialize_non_str_keys():
      d = {1: "one", 2: "two"}
      assert restore(flatten(d)) == d
  
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 3 for calling a global function with example usage: test_serialize_non_str_keys() without return types