code: def freq(self):
      return self._freq
  
imports: from __future__ import annotations
  import json
  import pyarrow
  from pandas._typing import IntervalClosedType
  from pandas.core.arrays.interval import VALID_CLOSED
label_desc: Use image node_id 2 for calling the ArrowPeriodType obj's underlying member method code with example usage: obj.freq() and returns: self