code: def test_size_period_index():
      # https://github.com/pandas-dev/pandas/issues/34010
      ser = Series([1], index=PeriodIndex(["2000"], name="A", freq="D"))
      grp = ser.groupby(level="A")
      result = grp.size()
      tm.assert_series_equal(result, ser)
  
file_path: pandas/pandas/tests/groupby/methods/test_size.py
imports: import numpy
  import pytest
  import pandas.util._test_decorators
  from pandas.core.dtypes.common import is_integer_dtype
  from pandas import DataFrame, Index, PeriodIndex, Series
  import pandas._testing
label_desc: Use image node_id 6 for calling a global function with example usage: test_size_period_index() without return types