code: def test_struct_null_count_10130() -> None:
      a_0 = pl.DataFrame(
          {"x": [None, 0, 0, 1, 1], "y": [0, 0, 1, 0, 1]}
      ).to_struct("xy")
      a_1 = pl.DataFrame(
          {"x": [2, 0, 0, 1, 1], "y": [0, 0, 1, 0, 1]}
      ).to_struct("xy")
      a_2 = pl.DataFrame(
          {"x": [2, 0, 0, 1, 1], "y": [0, 0, None, 0, 1]}
      ).to_struct("xy")
      assert a_0.null_count() == 0
      assert a_1.null_count() == 0
      assert a_2.null_count() == 0
  
      b_0 = pl.DataFrame(
          {
              "x": [1, None, 0, 0, 1, 1, None],
              "y": [None, 0, None, 0, 1, 0, 1],
          }
      ).to_struct("xy")
      b_1 = pl.DataFrame(
          {
              "x": [None, None, 0, 0, 1, 1, None],
              "y": [None, 0, None, 0, 1, 0, 1],
          }
      ).to_struct("xy")
      assert b_0.null_count() == 0
      assert b_1.null_count() == 1
  
      c_0 = pl.DataFrame({"x": [None, None]}).to_struct("x")
      c_1 = pl.DataFrame({"y": [1, 2], "x": [None, None]}).to_struct(
          "xy"
      )
      c_2 = pl.DataFrame({"x": [None, None], "y": [1, 2]}).to_struct(
          "xy"
      )
      assert c_0.null_count() == 2
      assert c_1.null_count() == 0
      assert c_2.null_count() == 0
  
      # There was an issue where it could ignore parts of a multi-chunk Series
      s = pl.Series([{"a": 1, "b": 2}])
      r = pl.Series(
          [{"a": None, "b": None}],
          dtype=pl.Struct({"a": pl.Int64, "b": pl.Int64}),
      )
      s.append(r)
      assert s.null_count() == 1
  
      s = pl.Series([{"a": None}])
      assert s.null_count() == 1
  
imports: from __future__ import annotations
  from dataclasses import dataclass
  from datetime import datetime, time
  from typing import TYPE_CHECKING
  import pandas
  import pyarrow
  import pytest
  import polars
  import polars.selectors
  from polars.testing import assert_frame_equal, assert_series_equal
label_desc: Use image node_id 47 for calling a global function with example usage: test_struct_null_count_10130() without return types