code: def test_eager_struct() -> None:
      with pytest.raises(
          pl.DuplicateError, match="multiple fields with name '' found"
      ):
          s = pl.struct(
              [pl.Series([1, 2, 3]), pl.Series(["a", "b", "c"])],
              eager=True,
          )
  
      s = pl.struct(
          [pl.Series("a", [1, 2, 3]), pl.Series("b", ["a", "b", "c"])],
          eager=True,
      )
      assert s.dtype == pl.Struct
  
imports: from __future__ import annotations
  from datetime import date, datetime
  from typing import TYPE_CHECKING
  import pytest
  import polars
  from polars.testing import assert_frame_equal, assert_series_equal
label_desc: Use image node_id 18 for calling a global function with example usage: test_eager_struct() without return types