code: def test_periods_serde(freq):
      ps = zb.periods("2020", freq, 20)
  
      assert ps[0] == serde.decode(serde.encode(ps[0]))
      assert ps == serde.decode(serde.encode(ps))
  
file_path: gluonts/test/zebras/test_period.py
imports: import pytest
  import numpy
  import pandas
  from pandas.tseries.frequencies import to_offset
  from gluonts.core import serde
  import gluonts.zebras
label_desc: Use image node_id 6 for calling a global function with example usage: test_periods_serde(freq) without return types