code: def test_astype_dt64tz_to_str(self, timezone_frame):
      # str formatting
      result = timezone_frame.astype(str)
      expected = DataFrame(
          [
              [
                  "2013-01-01",
                  "2013-01-01 00:00:00-05:00",
                  "2013-01-01 00:00:00+01:00",
              ],
              ["2013-01-02", "NaT", "NaT"],
              [
                  "2013-01-03",
                  "2013-01-03 00:00:00-05:00",
                  "2013-01-03 00:00:00+01:00",
              ],
          ],
          columns=timezone_frame.columns,
          dtype="object",
      )
      tm.assert_frame_equal(result, expected)
  
      with option_context("display.max_columns", 20):
          result = str(timezone_frame)
          assert (
              "0 2013-01-01 2013-01-01 00:00:00-05:00 2013-01-01 00:00:00+01:00"
          ) in result
          assert (
              "1 2013-01-02                       NaT                       NaT"
          ) in result
          assert (
              "2 2013-01-03 2013-01-03 00:00:00-05:00 2013-01-03 00:00:00+01:00"
          ) in result
  
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 31 for calling the TestAstype obj's underlying member method code with example usage: obj.test_astype_dt64tz_to_str(timezone_frame) without return types