祖先查询解析错误
我正在尝试让我的祖先查询正常工作，但我一直收到这个错误：
BadQueryError: 解析错误：标识符是一个保留关键字，出现在符号 ANCESTOR
错误出现在这一行：
TweepleKey(twitter_handle))
我在按照使用数据存储的教程（这个教程是有效的）进行操作，但当我尝试将祖先查询的概念应用到我的代码中（见下文）时，它总是出现上面提到的错误。我哪里出错了呢？
import cgi
import urllib
import webapp2
import cgi
from google.appengine.ext import db
# defines a data model for a geotweet
# GeoTweet model has 1 property: twitter_handle
class GeoTweet(db.Model):
twitter_handle = db.StringProperty()
date = db.DateTimeProperty(auto_now_add=True)
def TweepleKey(twitter_handle=None):
# Constructs a Datastore key for a TweepleStore entity with twitter_handle
return db.Key.from_path('TweepleStore', twitter_handle or 'default_handle')
class MainPage(webapp2.RequestHandler):
def get(self):
self.response.out.write("""<html><body>""")
twitter_handle = self.request.get('twitter_handle')
tweeple = db.GqlQuery("SELECT * "
"FROM GeoTweet "
"WHERE ANCESTOR = :1 "
"ORDER BY date DESC LIMIT 10",
TweepleKey(twitter_handle))
for t in tweeple:
if t.twitter_handle:
self.out.write('<b>Found %s. Saved on %s.</b>' % (t.twitter_handle, t.date))
else:
self.out.write('<b>%s was not found!' % twitter_handle)
self.response.out.write("""<form action="/search" method="post">
<div><textarea name="twitter_handle" rows="1" cols="20">@example</textarea>
<div><input type="submit" value="Find"></div>
</form>
</body>
</html>""")
class TweepleStore(webapp2.RequestHandler):
def post(self):
twitter_name = self.request.get('twitter_handle')
geotweet = GeoTweet(parent=TweepleKey(twitter_name))
geotweet.twitter_handle = twitter_name
geotweet.put()
self.redirect('/?' + urllib.urlencode({'twitter_name': twitter_name}))
app = webapp2.WSGIApplication([('/', MainPage),
('/search', TweepleStore)], debug=True)