code: def test_year_month(dt):
      fmt = "%Y-%m"
      dtstr = dt.strftime(fmt)
  
      assert isoparse(dtstr) == dt
  
imports: from __future__ import unicode_literals
  from datetime import datetime, timedelta, date, time
  import itertools
  from dateutil import tz
  from dateutil.tz import UTC
  from dateutil.parser import isoparser, isoparse
  import pytest
  import six
label_desc: Use image node_id 3 for calling a global function with example usage: test_year_month(dt) without return types