c2m  - UTC calendar to MJD[TAI]

def invoke (self, args, **kwargs):
        """c2m  - UTC calendar to MJD[TAI]"""

        if len (args) not in (3, 6):
            raise multitool.UsageError ('c2m expected exactly 3 or 6 arguments')

        year = int (args[0])
        month = int (args[1])

        import astropy.time

        if len (args) == 3:
            day = float (args[2])
            iday = int (math.floor (day))
            r = 24 * (day - iday)
            hour = int (np.floor (r))
            r = 60 * (r - hour)
            minute = int (np.floor (r))
            second = 60 * (r - minute)
        else:
            iday = int (args[2])
            hour = int (args[3])
            minute = int (args[4])
            second = float (args[5])

        s = '%d-%02d-%02d %02d:%02d:%02.8f' % (year, month, iday,
                                               hour, minute, second)
        t = astropy.time.Time (s, format='iso', scale='utc')
        print ('%.4f' % t.tai.mjd)