code: def test_iterate_flattened():
      d = {"a": {"aa": 1, "ab": {"aba": 8}}, "b": 3}
      assert list(iterate_flattened(d)) == [
          ("a.aa", 1),
          ("a.ab.aba", 8),
          ("b", 3),
      ]
  
imports: import pytest
  from sacred.utils import PATHCHANGE, convert_to_nested_dict, get_by_dotted_path, is_prefix, iter_prefixes, iterate_flattened, iterate_flattened_separately, join_paths, recursive_update, set_by_dotted_path, get_inheritors, convert_camel_case_to_snake_case, apply_backspaces_and_linefeeds, module_exists, module_is_in_cache, get_package_version, parse_version, rel_path
label_desc: Use image node_id 3 for calling a global function with example usage: test_iterate_flattened() without return types