code: def test_overflow_uint16_agg_mean() -> None:
      assert (
          pl.DataFrame(
              {
                  "col1": ["A" for _ in range(1025)],
                  "col3": [64 for i in range(1025)],
              }
          )
          .with_columns(
              [
                  pl.col("col3").cast(pl.UInt16),
              ]
          )
          .group_by(["col1"])
          .agg(pl.col("col3").mean())
          .to_dict(as_series=False)
      ) == {"col1": ["A"], "col3": [64.0]}
  
imports: from __future__ import annotations
  from datetime import datetime, timedelta
  from typing import Any
  import numpy
  import pandas
  import polars
  from polars.testing import assert_frame_equal
label_desc: Use image node_id 4 for calling a global function with example usage: test_overflow_uint16_agg_mean() without return types