code: def test_to_timestamp_quarterly_bug(self):
      years = np.arange(1960, 2000).repeat(4)
      quarters = np.tile(list(range(1, 5)), 40)
  
      pindex = PeriodIndex.from_fields(year=years, quarter=quarters)
  
      stamps = pindex.to_timestamp("D", "end")
      expected = DatetimeIndex(
          [x.to_timestamp("D", "end") for x in pindex]
      )
      tm.assert_index_equal(stamps, expected)
      assert stamps.freq == expected.freq
  
file_path: pandas/pandas/tests/indexes/period/methods/test_to_timestamp.py
imports: from datetime import datetime
  import numpy
  import pytest
  from pandas import DatetimeIndex, NaT, PeriodIndex, Timedelta, Timestamp, date_range, period_range
  import pandas._testing
label_desc: Use image node_id 5 for calling the TestToTimestamp obj's underlying member method code with example usage: obj.test_to_timestamp_quarterly_bug() without return types