code: def test_astype_object(self):
      idx = PeriodIndex([], freq="M")
  
      exp = np.array([], dtype=object)
      tm.assert_numpy_array_equal(idx.astype(object).values, exp)
      tm.assert_numpy_array_equal(idx._mpl_repr(), exp)
  
      idx = PeriodIndex(["2011-01", NaT], freq="M")
  
      exp = np.array([Period("2011-01", freq="M"), NaT], dtype=object)
      tm.assert_numpy_array_equal(idx.astype(object).values, exp)
      tm.assert_numpy_array_equal(idx._mpl_repr(), exp)
  
      exp = np.array(
          [Period("2011-01-01", freq="D"), NaT], dtype=object
      )
      idx = PeriodIndex(["2011-01-01", NaT], freq="D")
      tm.assert_numpy_array_equal(idx.astype(object).values, exp)
      tm.assert_numpy_array_equal(idx._mpl_repr(), exp)
  
file_path: pandas/pandas/tests/indexes/period/methods/test_astype.py
imports: import numpy
  import pytest
  from pandas import CategoricalIndex, DatetimeIndex, Index, NaT, Period, PeriodIndex, period_range
  import pandas._testing
label_desc: Use image node_id 4 for calling the TestPeriodIndexAsType obj's underlying member method code with example usage: obj.test_astype_object() without return types