code: def test_agg_tzaware_non_datetime_result(as_period):
      # discussed in GH#29589, fixed in GH#29641, operating on tzaware values
      #  with function that is not dtype-preserving
      dti = date_range("2012-01-01", periods=4, tz="UTC")
      if as_period:
          dti = dti.tz_localize(None).to_period("D")
  
      df = DataFrame({"a": [0, 0, 1, 1], "b": dti})
      gb = df.groupby("a")
  
      # Case that _does_ preserve the dtype
      result = gb["b"].agg(lambda x: x.iloc[0])
      expected = Series(dti[::2], name="b")
      expected.index.name = "a"
      tm.assert_series_equal(result, expected)
  
      # Cases that do _not_ preserve the dtype
      result = gb["b"].agg(lambda x: x.iloc[0].year)
      expected = Series([2012, 2012], name="b")
      expected.index.name = "a"
      tm.assert_series_equal(result, expected)
  
      result = gb["b"].agg(lambda x: x.iloc[-1] - x.iloc[0])
      expected = Series(
          [pd.Timedelta(days=1), pd.Timedelta(days=1)], name="b"
      )
      expected.index.name = "a"
      if as_period:
          expected = Series(
              [pd.offsets.Day(1), pd.offsets.Day(1)], name="b"
          )
          expected.index.name = "a"
      tm.assert_series_equal(result, expected)
  
imports: import datetime
  from functools import partial
  import numpy
  import pytest
  from pandas.errors import SpecificationError
  import pandas
  from pandas import DataFrame, Index, MultiIndex, PeriodIndex, Series, date_range, period_range
  import pandas._testing
  from pandas.io.formats.printing import pprint_thing
label_desc: Use image node_id 17 for calling a global function with example usage: test_agg_tzaware_non_datetime_result(as_period) without return types