Python3.x Python3.2 协程：AttributeError：生成器对象没有属性下一个

#!/usr/bin/python3.2
import sys

def match_text(pattern):
    line = (yield)
    if pattern in line:
        print(line)

x = match_text('apple')
x.next()

for line in input('>>>> '):
    if x.send(line):
        print(line)

x.close()

这是一个合作项目，但不是Python .2将其视为发电机——为什么？这是怎么回事？我指的是David Beazeley的《Python基本参考》，第20页.

引用相关章节:

Normally, functions operate on a single set of input arguments. However, a function can
also be written to operate as a task that processes a sequence of inputs sent to
it.This type of function is known as a coroutine and is created by using the yield 
statement as an expression (yield) as shown in this example:
 def print_matches(matchtext):
   print "Looking for", matchtext
   while True:
     line = (yield)       # Get a line of text
     if matchtext in line:
       print line

To use this function, you first call it, advance it to the first (yield), and then 
start sending data to it using send(). For example:
>>> matcher = print_matches("python")
>>> matcher.next() # Advance to the first (yield)
Looking for python
>>> matcher.send("Hello World")
>>> matcher.send("python is cool")
python is cool
>>> matcher.send("yow!")
>>> matcher.close() # Done with the matcher function call

为什么我的代码不起作用-DB不起作用..

deathstar> python3.2 xxx   
Traceback (most recent call last):
  File "xxx", line 9, in <module>
    matcher.next() # Advance to the first (yield)
AttributeError: 'generator' object has no attribute 'next'