Cómo mostrar una barra de progreso en modo consola

import sys,time

class Progress:
    '''Progress display for console applications.

    See __main__ block at end of file for sample usage.
    '''
    def __init__(self, info, sequence):
        self.info = info
        self.sequence = iter(sequence)
        self.total = len(sequence)
        self.start = self.now = time.time()
        self.num = 0
        self.stepsize = self.total / 100 or 1
        self.steptimes = []
        self.display()

    def __iter__(self): return self

    def next(self):
        self.num += 1

        if self.num > self.total:
            print self.info, 'done', ' '*(75-len(self.info)-6)
            sys.stdout.flush()
            return self.sequence.next()

        if self.num % self.stepsize:
            return self.sequence.next()

        self.display()
        return self.sequence.next()

    def display(self):
        # figure how long we've spent - guess how long to go
        now = time.time()
        steptime = now - self.now
        self.steptimes.insert(0, steptime)
        if len(self.steptimes) > 5:
            self.steptimes.pop()
        steptime = sum(self.steptimes) / len(self.steptimes)
        self.now = now
        eta = steptime * ((self.total - self.num)/self.stepsize)

        # tell it like it is (or might be)
        if now - self.start > 3:
            M = eta / 60
            H = M / 60
            M = M % 60
            S = eta % 60
            s = '%s %2d%% (ETA %02d:%02d:%02d)'%(self.info,
                self.num * 100. / self.total, H, M, S)
        else:
            s = '%s %2d%%'%(self.info, self.num * 100. / self.total)
        sys.stdout.write(s + ' '*(75-len(s)) + '\r')
        sys.stdout.flush()

if __name__ == '__main__':
    for i in Progress('Testing 3...', range(3)):
        time.sleep(5)
    for i in Progress('Testing 1645...', range(1645)):
        time.sleep(.01)