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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def purge_one(calc_id, user):
 """ Remove one calculation ID from the database and remove its datastore """

    filename = os.path.join(datadir, 'calc_%s.hdf5' % calc_id)
    err = dbcmd('del_calc', calc_id, user)
    if err:
        print(err)
    elif os.path.exists(filename):  # not removed yet
        os.remove(filename)
        print('Removed %s' % filename)