code: def test_map_box_period():
      # period
      vals = [
          pd.Period("2011-01-01", freq="M"),
          pd.Period("2011-01-02", freq="M"),
      ]
      ser = Series(vals)
      assert ser.dtype == "Period[M]"
      res = ser.map(lambda x: f"{type(x).__name__}_{x.freqstr}")
      exp = Series(["Period_M", "Period_M"])
      tm.assert_series_equal(res, exp)
  
imports: from collections import Counter, defaultdict
  from decimal import Decimal
  import math
  import numpy
  import pytest
  import pandas
  from pandas import DataFrame, Index, MultiIndex, Series, bdate_range, date_range, isna, timedelta_range
  import pandas._testing
label_desc: Use image node_id 39 for calling a global function with example usage: test_map_box_period() without return types