title: Problem declaring global variable in python/GAE
body: <p>I'm new to python and I'm trying to obtain a username from the UI and query the result to get the phone book contacts of the user. But I am not able to set the user name to be a global variable to use it for multiple queries. Here's the code, I believe I am doing some syntax error/improper usage, please help out in correcting my code.</p>
  
  <pre><code>#!/usr/bin/env python
  
  import wsgiref.handlers
  from google.appengine.ext import db
  from google.appengine.ext import webapp
  from google.appengine.ext.webapp import template
  import models
  
  class showPhoneBook(db.Model):
      username = db.StringProperty(required=True)
  
  class MyHandler(webapp.RequestHandler):
      user_name = ''
      def get(self):
          p = db.GqlQuery('SELECT * FROM UserDetails WHERE user_name = $1', user_name)
          #p = UserDetails.gql('WHERE user_name = $1', user_name)
          result1 = p.fetch(1)
          for itr1 in result1:
              userId = itr.user_id
          q = db.GqlQuery('SELECT * FROM PhoneBook WHERE user_id = :1', userId)
          #q = PhoneBook.gql('WHERE user_id = :1', userId)
          values = {
              'phoneBookValues': q
          }
          self.request.out.write(
              template.render('phonebook.html', values))
      def post(self):
          global user_name
          phoneBookuserID = showPhoneBook(
              user_name = self.request.get(
                  'username'))
          self.request.out.write(user_name)
          phonebookuserID.put()
          self.redirect('/')
  
  def main():
      app = webapp.WSGIApplication([
          (r'.*',MyHandler)], debug=True)
      wsgiref.handlers.CGIHandler().run(app)
  
  if __name__ == "__main__":
      main()
  </code></pre>
  
  <p>Here <strong>UserDetails</strong> and <strong>Phonebook</strong> are my entity classes defined in my <strong>models.py</strong></p>
  
  <p>Please Help me in finding the error...or possibly get a corrected code of how to use user_name in queries after obtaining it from the UI.</p>