code: def test_interpolate_period_values(self):
      orig = Series(date_range("2012-01-01", periods=5))
      ser = orig.copy()
      ser[2] = pd.NaT
  
      # period cast
      ser_per = ser.dt.to_period("D")
      res_per = ser_per.interpolate()
      expected_per = orig.dt.to_period("D")
      tm.assert_series_equal(res_per, expected_per)
  
imports: import numpy
  import pytest
  import pandas.util._test_decorators
  import pandas
  from pandas import Index, MultiIndex, Series, date_range, isna
  import pandas._testing
label_desc: Use image node_id 1 for calling the TestSeriesInterpolateData obj's underlying member method code with example usage: obj.test_interpolate_period_values() without return types