def str2ms(s):
    """convert DDMM.MMMMMM string to arc milliseconds(int)"""
    if s == b'':
        return None
    dm, frac = (b'0000' + s).split(b'.')
    return round((int(dm[:-2]) * 60 + float(dm[-2:] + b'.' + frac)) * 60000)
