code: def test_astype_to_sparse_dt64(self):
      # GH#50082
      dti = pd.date_range("2016-01-01", periods=4)
      dta = dti._data
      result = dta.astype("Sparse[datetime64[ns]]")
  
      assert result.dtype == "Sparse[datetime64[ns]]"
      assert (result == dta).all()
  
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 7 for calling the TestDatetimeArray obj's underlying member method code with example usage: obj.test_astype_to_sparse_dt64() without return types