关于python和simpy，谁用过啊？

from __future__ import generators # Python 2.2 only
from SimPy.Simulation import *
from random import uniform
class Car(Process):
def __init__(self,id):
Process.__init__(self)
self.id=id
def carDriving(self,driveTime):
# the Process Execution Method (generator)
print "%5.1f %s started" %(now(),self.id)
yield hold,self,driveTime
print "%5.1f %s arrived" %(now(),self.id)
initialize()
nrCars=10for i in range(nrCars):
c=Car(id="Car %s" %i) activate(c,c.carDriving(driveTime=uniform(1,90)))
simulate(until=100)