<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def process_dut(dut):
 """ Signal worker thread that specified Dut needs processing """

        if dut.finished():
            return
        Dut._signalled_duts.appendleft(dut)
        Dut._sem.release()