code: def test_utc_timestamping():
      t = datetime(2017, 7, 14, 2, 40).replace(tzinfo=timezone.utc)
      assert timestamp(t) == 1500000000
  
      for d in (
          datetime.now(),
          datetime.utcnow(),
          datetime(1999, 12, 31, 23, 59, 59),
          datetime(2000, 1, 1, 0, 0, 0),
      ):
          assert datetime.utcfromtimestamp(
              timestamp(d)
          ) - d < timedelta(microseconds=10)
  
file_path: pygal/pygal/test/test_date.py
imports: from datetime import date, datetime, time, timedelta, timezone
  from pygal import DateLine, DateTimeLine, TimeDeltaLine, TimeLine
  from pygal._compat import timestamp
  from pygal.test.utils import texts
label_desc: Use image node_id 7 for calling a global function with example usage: test_utc_timestamping() without return types