有两种类型的回调函数：
代码如下:
blocking callbacks (also known as synchronous callbacks or just callbacks)deferred callbacks (also known as asynchronous callbacks)
那么，在python中如何实现回调函数呢，看代码：
代码如下:
def my_callback(input): print “function my_callback was called with %s input” % (input,)def caller(input, func): func(input)for i in range(5): caller(i, my_callback)