code: def test_struct_field_iter() -> None:
      s = Struct(
          [
              Field("a", List(List(Int64))),
              Field("b", List(Int64)),
              Field("c", Int64),
          ]
      )
      assert list(s) == [
          ("a", List(List(Int64))),
          ("b", List(Int64)),
          ("c", Int64),
      ]
      assert list(reversed(s)) == [
          ("c", Int64),
          ("b", List(Int64)),
          ("a", List(List(Int64))),
      ]
  
file_path: polars/py-polars/tests/unit/test_datatypes.py
imports: from __future__ import annotations
  import pickle
  from datetime import datetime, timedelta
  from typing import TYPE_CHECKING
  import pytest
  import polars
  from polars import datatypes
  from polars.datatypes import DTYPE_TEMPORAL_UNITS, DataTypeGroup, Field, Int64, List, Struct, py_type_to_dtype
label_desc: Use image node_id 12 for calling a global function with example usage: test_struct_field_iter() without return types