code: def test_astype_tz_object_conversion(self, tz):
      # GH 35973
      val = {
          "tz": date_range(
              "2020-08-30", freq="d", periods=2, tz="Europe/London"
          )
      }
      expected = DataFrame(val)
  
      # convert expected to object dtype from other tz str (independently tested)
      result = expected.astype({"tz": f"datetime64[ns, {tz}]"})
      result = result.astype({"tz": "object"})
  
      # do real test: object dtype to a specified tz, different from construction tz.
      result = result.astype({"tz": "datetime64[ns, Europe/London]"})
      tm.assert_frame_equal(result, expected)
  
imports: import re
  import numpy
  import pytest
  import pandas.util._test_decorators
  import pandas
  from pandas import Categorical, CategoricalDtype, DataFrame, DatetimeTZDtype, Index, Interval, IntervalDtype, NaT, Series, Timedelta, Timestamp, concat, date_range, option_context
  import pandas._testing
label_desc: Use image node_id 35 for calling the TestAstype obj's underlying member method code with example usage: obj.test_astype_tz_object_conversion(tz) without return types