code: def test_groupby_datetime64_32_bit(self):
      # GH 6410 / numpy 4328
      # 32-bit under 1.9-dev indexing issue
  
      df = DataFrame({"A": range(2), "B": [Timestamp("2000-01-1")] * 2})
      result = df.groupby("A")["B"].transform("min")
      expected = Series([Timestamp("2000-01-1")] * 2, name="B")
      tm.assert_series_equal(result, expected)
  
imports: from datetime import datetime, timedelta
  import numpy
  import pytest
  import pytz
  import pandas
  from pandas import DataFrame, DatetimeIndex, Index, MultiIndex, Series, Timestamp, date_range, offsets
  import pandas._testing
  from pandas.core.groupby.grouper import Grouper
  from pandas.core.groupby.ops import BinGrouper
label_desc: Use image node_id 16 for calling the TestGroupBy obj's underlying member method code with example usage: obj.test_groupby_datetime64_32_bit() without return types