code: def test_dropna_period_dtype(self):
      # GH#13737
      ser = Series(
          [Period("2011-01", freq="M"), Period("NaT", freq="M")]
      )
      result = ser.dropna()
      expected = Series([Period("2011-01", freq="M")])
  
      tm.assert_series_equal(result, expected)
  
file_path: pandas/pandas/tests/series/methods/test_dropna.py
imports: import numpy
  import pytest
  from pandas import DatetimeIndex, IntervalIndex, NaT, Period, Series, Timestamp
  import pandas._testing
label_desc: Use image node_id 5 for calling the TestDropna obj's underlying member method code with example usage: obj.test_dropna_period_dtype() without return types