如何修复unicodeencodeerror＆＃39; ascii＆＃39;编解码器无法对字符进行编码

Question

我有这张用python编写的代码：

import urllib
from BeautifulSoup import BeautifulSoup
from yattag import Doc, indent

urls = []
sock1 = urllib.urlopen("http://www.tubtun.com/videos/")
htmlSource1 = sock1.read()
sock1.close()
soup1 = BeautifulSoup(htmlSource1)
f = open ('sitemap.xml','w');
for i in soup1.findAll('a'):
    if (i.get('href')):
        if (i["href"].find("http://www.tubtun.com/video/") == 0):
            if(i["href"][0:1]=="u'"):
                i["href"]=i["href"][2:]
            sock = urllib.urlopen(i["href"])
            htmlSource = sock.read()
            sock.close()
            soup = BeautifulSoup(htmlSource)
            thumbnailUrl = soup.find('meta',{'itemprop':"thumbnailUrl"})
            name = soup.find('meta',{'itemprop':"name"})
            description = soup.find('meta',{'itemprop':"description"})
            duration = soup.find('meta',{'itemprop':"duration"})
            contentURL = soup.find('meta',{'itemprop':"contentURL"})
            embedURL = soup.find('meta',{'itemprop':"embedURL"})
            uploadDate = soup.find('meta',{'itemprop':"uploadDate"})
            vif = soup.find('meta',{'property':"og:video"})
            doc, tag, text = Doc().tagtext()
            with tag('url'):
                    with tag('loc'):
                        text(i["href"])
                    with tag('video:video'):
                        with tag('video:title'):
                            text(name["content"])
                        with tag('video:description'):
                            text(description["content"])
                        with tag('video:thumbnail_loc'):
                            text(thumbnailUrl["content"])
                        with tag('video:player_loc'):
                            text(vif["content"])
                        with tag('video:publication_date'):
                            text(uploadDate["content"][0:10])
            result = indent(
                doc.getvalue(),
                indentation = ' '*4,
                newline = '\r\n'
            )
            f.write(result)
f.close()

该脚本为tubtun.com网站生成站点地图视频。

运行脚本时出现此错误：

  

unicodeencodeerror＆＃39; ascii＆＃39;编解码器不能编码字符

解决这个问题的任何解决方案？