code: def dtype(self, unit, tz_naive_fixture):
      tz = tz_naive_fixture
      if tz is None:
          return np.dtype(f"datetime64[{unit}]")
      else:
          return DatetimeTZDtype(unit=unit, tz=tz)
  
imports: from __future__ import annotations
  from datetime import timedelta
  import operator
  import numpy
  import pytest
  from pandas._libs.tslibs import tz_compare
  from pandas.core.dtypes.dtypes import DatetimeTZDtype
  import pandas
  import pandas._testing
  from pandas.core.arrays import DatetimeArray, TimedeltaArray
label_desc: Use image node_id 2 for calling the TestNonNano obj's underlying member method code with example usage: obj.dtype(unit, tz_naive_fixture) and returns: np, DatetimeTZDtype