大侠请留步！python多线程调用tcl脚本有关问题

大侠请留步！！！python多线程调用tcl脚本问题。
我用python起了多线程去调用不同的tcl文件。
tcl.eval处，为什么不是并行？好像是串行呢？

Python code

#起3个线程    threadNum = 3                          threads = []    for i in range(threadNum):        data = 'test'        for j in range(VALUENUMBER):            data = data+' '+DataList[j][i]        res = ProductsTest(i,data,para)        threads.append(res)      for i in range(threadNum):        threads[i].start()    for i in range(threadNum):        threads[i].join()################################################################import Tkinterimport tracebacktcl = Tkinter.Tcl()class ProductsTest(threading.Thread):     def __init__(self, num, data,para):           threading.Thread.__init__(self)           self.thread_num = num           self.data = data        self.para = para            def run(self):              global tcl        starttime = time.clock()        returnFromTcl = ''        SCRIPTPATH1= "test1.tcl"        SCRIPTPATH2= "test2.tcl"        SCRIPTPATH3= "test3.tcl"        if self.thread_num == 1:            tcl.eval('source '+ SCRIPTPATH1)            returnFromTcl = tcl.eval(self.data)             elif self.thread_num == 2:            tcl.eval('source '+ SCRIPTPATH2)            returnFromTcl = tcl.eval(self.data)             else:            tcl.eval('source '+ SCRIPTPATH3)            returnFromTcl = tcl.eval(self.data)             Time= time.clock() - starttime