code: def test_fillna_datetime_inplace(self):
      # GH#48863
      df = DataFrame(
          {
              "date1": to_datetime(["2018-05-30", None]),
              "date2": to_datetime(["2018-09-30", None]),
          }
      )
      expected = df.copy()
      df.fillna(np.nan, inplace=True)
      tm.assert_frame_equal(df, expected)
  
imports: import numpy
  import pytest
  from pandas._config import using_pyarrow_string_dtype
  from pandas import Categorical, DataFrame, DatetimeIndex, NaT, PeriodIndex, Series, TimedeltaIndex, Timestamp, date_range, to_datetime
  import pandas._testing
  from pandas.tests.frame.common import _check_mixed_float
label_desc: Use image node_id 38 for calling the TestFillNA obj's underlying member method code with example usage: obj.test_fillna_datetime_inplace() without return types