python的爬取html网页错误

 import requests
import xml.etree.ElementTree as ET
from xml.parsers.expat import ParserCreate

class DefaultSaxHandler(object):
    def __init__(self, provinces):
        self.provinces = provinces


    def start_element(self, name, attrs):
        pass

    def end_element(self, name):
        pass


    def char_data(self, text):
        self.provinces.append((text))

def get_province_entry(url):

    content = requests.get(url).content.decode('gb2312')

    start = content.find('<table height="22" cellSpacing="0" cellPadding="0" width="710" border="0">')
    end = content.find('<tr align="middle">')
    content = content[start:end ].strip()
    print(content)
    provinces = []

    handler = DefaultSaxHandler(provinces)

    parser = ParserCreate()
    parser.StartElementHandler = handler.start_element
    parser.EndElementHandler = handler.end_element
    parser.CharacterDataHandler = handler.char_data

    parser.Parse(content)

    return provinces

provinces = get_province_entry('http://www.ip138.com/post/')
print(provinces)

我想问下为什么打印出空值，我觉得是这部分错了，但是说不出哪里错

  def char_data(self, text):
        self.provinces.append((text))

因为源码中

<table height="22" cellSpacing="0" cellPadding="0" width="710" border="0">

下一行就是

 <tr align="middle">

，所以造成content是空值