def dateTimeToString(dateTime, convertToUTC=False):
    """
    Ignore tzinfo unless convertToUTC.  Output string.
    """
    if dateTime.tzinfo and convertToUTC:
        dateTime = dateTime.astimezone(utc)

    datestr = "{}{}{}T{}{}{}".format(
        numToDigits(dateTime.year, 4),
        numToDigits(dateTime.month, 2),
        numToDigits(dateTime.day, 2),
        numToDigits(dateTime.hour, 2),
        numToDigits(dateTime.minute, 2),
        numToDigits(dateTime.second, 2),
    )
    if tzinfo_eq(dateTime.tzinfo, utc):
        datestr += "Z"
    return datestr