code: def test_dti_drop_dont_lose_tz(self):
      # GH#2621
      ind = date_range("2012-12-01", periods=10, tz="utc")
      ind = ind.drop(ind[-1])
  
      assert ind.tz is not None
  
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 1 for calling the TestDatetimeIndexTimezones obj's underlying member method code with example usage: obj.test_dti_drop_dont_lose_tz() without return types