code: def test_dti_tz_conversion_freq(self, tz_naive_fixture):
      # GH25241
      t3 = DatetimeIndex(["2019-01-01 10:00"], freq="h")
      assert t3.tz_localize(tz=tz_naive_fixture).freq == t3.freq
      t4 = DatetimeIndex(["2019-01-02 12:00"], tz="UTC", freq="min")
      assert t4.tz_convert(tz="UTC").freq == t4.freq
  
imports: from datetime import datetime, timedelta, timezone, tzinfo
  from dateutil.tz import gettz
  import numpy
  import pytest
  import pytz
  from pandas._libs.tslibs import conversion, timezones
  import pandas
  from pandas import DatetimeIndex, Timestamp, bdate_range, date_range, isna, to_datetime
  import pandas._testing
label_desc: Use image node_id 2 for calling the TestDatetimeIndexTimezones obj's underlying member method code with example usage: obj.test_dti_tz_conversion_freq(tz_naive_fixture) without return types