def dt_str_to_posix(dt_str):
  parsable, _ = dt_str.split('.')
  dt = datetime.datetime.strptime(parsable, _DT_FORMAT)
  return calendar.timegm(dt.utctimetuple())
format str to posix.
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/ext/cloudstorage/common.py/dt_str_to_posix