code: def test_month_start_end_invalid() -> None:
      ser = pl.Series([time(1, 2, 3)])
      with pytest.raises(
          InvalidOperationError,
          match=r"`month_start` operation not supported for dtype `time` \(expected: date/datetime\)",
      ):
          ser.dt.month_start()
      with pytest.raises(
          InvalidOperationError,
          match=r"`month_end` operation not supported for dtype `time` \(expected: date/datetime\)",
      ):
          ser.dt.month_end()
  
imports: from __future__ import annotations
  import sys
  from datetime import date, datetime, time, timedelta
  from typing import TYPE_CHECKING
  import pytest
  import polars
  from polars.datatypes import DTYPE_TEMPORAL_UNITS
  from polars.dependencies import _ZONEINFO_AVAILABLE
  from polars.exceptions import ComputeError, InvalidOperationError
  from polars.testing import assert_frame_equal, assert_series_equal
label_desc: Use image node_id 16 for calling a global function with example usage: test_month_start_end_invalid() without return types