def force_utc(time, name='field', precision=6):
    """Appending 'Z' to isoformatted time - explicit timezone is required for most APIs"""
    if not isinstance(time, datetime.datetime):
        raise CloudValueError("%s should be of type datetime" % (name,))
    clip = 6 - precision
    timestring = time.isoformat()
    if clip:
        timestring = timestring[:-clip]
    return timestring + "Z"
Appending 'Z' to isoformatted time - explicit timezone is required for most APIs