def METHOD_NAME(rec, msg, cpu0=None, wall0=None):
    if cpu0 is None:
        cpu0 = rec._t0
    if wall0:
        rec._t0, rec._w0 = process_clock(), perf_counter()
        if rec.verbose >= TIMER_LEVEL:
            flush(rec, '    CPU time for %s %9.2f sec, wall time %9.2f sec'
                  % (msg, rec._t0-cpu0, rec._w0-wall0))
        return rec._t0, rec._w0
    else:
        rec._t0 = process_clock()
        if rec.verbose >= TIMER_LEVEL:
            flush(rec, '    CPU time for %s %9.2f sec' % (msg, rec._t0-cpu0))
        return rec._t0