class Test(webapp.RequestHandler):
    def get(self):
    
        s = self.request.get('sentence')
        if not hasattr(self, 'mylist'):
            mylist = []          
            try:
                htmlcode1 = HTML.table(mylist)
            except TypeError:
                htmlcode1 = HTML.table('empty table')
        mylist.append(s)

Traceback (most recent call last):
  Line 1, in <module>
    class Test(webapp.RequestHandler):
NameError: name 'webapp' is not defined