code: def test_constructor_use_start_freq(self):
      # GH #1118
      msg1 = "Period with BDay freq is deprecated"
      with tm.assert_produces_warning(FutureWarning, match=msg1):
          p = Period("4/2/2012", freq="B")
      msg2 = r"PeriodDtype\[B\] is deprecated"
      with tm.assert_produces_warning(FutureWarning, match=msg2):
          expected = period_range(
              start="4/2/2012", periods=10, freq="B"
          )
  
      with tm.assert_produces_warning(FutureWarning, match=msg2):
          index = period_range(start=p, periods=10)
      tm.assert_index_equal(index, expected)
  
imports: import numpy
  import pytest
  from pandas._libs.tslibs.period import IncompatibleFrequency
  from pandas.core.dtypes.dtypes import PeriodDtype
  from pandas import Index, NaT, Period, PeriodIndex, Series, date_range, offsets, period_range
  import pandas._testing
  from pandas.core.arrays import PeriodArray
label_desc: Use image node_id 6 for calling the TestPeriodIndex obj's underlying member method code with example usage: obj.test_constructor_use_start_freq() without return types