<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def mjd2date(mjd, precision=3):
 """Convert an MJD to a data string in the format used by CASA. mjd (numeric) An MJD value in the UTC timescale. precision (integer, default 3) The number of digits of decimal precision in the seconds portion of the returned string Returns A string representing the input argument in CASA format: ``YYYY/MM/DD/HH:MM:SS.SSS``. Example:: from pwkit.environment.casa import tasks print(tasks.mjd2date(55555)) # yields '2010/12/25/00:00:00.000' """

    from astropy.time import Time
    dt = Time(mjd, format='mjd', scale='utc').to_datetime()
    fracsec = ('%.*f' % (precision, 1e-6 * dt.microsecond)).split('.')[1]
    return '%04d/%02d/%02d/%02d:%02d:%02d.%s' % (
        dt.year, dt.month, dt.day, dt.hour, dt.minute, dt.second, fracsec
    )