code: def test_where_invalid_dtypes(self):
      pi = period_range("20130101", periods=5, freq="D")
  
      tail = pi[2:].tolist()
      i2 = PeriodIndex([NaT, NaT] + tail, freq="D")
      mask = notna(i2)
  
      result = pi.where(mask, i2.asi8)
      expected = pd.Index([NaT._value, NaT._value] + tail, dtype=object)
      assert isinstance(expected[0], int)
      tm.assert_index_equal(result, expected)
  
      tdi = i2.asi8.view("timedelta64[ns]")
      expected = pd.Index([tdi[0], tdi[1]] + tail, dtype=object)
      assert isinstance(expected[0], np.timedelta64)
      result = pi.where(mask, tdi)
      tm.assert_index_equal(result, expected)
  
      dti = i2.to_timestamp("s")
      expected = pd.Index([dti[0], dti[1]] + tail, dtype=object)
      assert expected[0] is NaT
      result = pi.where(mask, dti)
      tm.assert_index_equal(result, expected)
  
      td = Timedelta(days=4)
      expected = pd.Index([td, td] + tail, dtype=object)
      assert expected[0] == td
      result = pi.where(mask, td)
      tm.assert_index_equal(result, expected)
  
imports: from datetime import datetime
  import re
  import numpy
  import pytest
  from pandas._libs.tslibs import period
  from pandas.errors import InvalidIndexError
  import pandas
  from pandas import DatetimeIndex, NaT, Period, PeriodIndex, Series, Timedelta, date_range, notna, period_range
  import pandas._testing
label_desc: Use image node_id 3 for calling the TestWhere obj's underlying member method code with example usage: obj.test_where_invalid_dtypes() without return types