title: Exception Handling in google app engine
body: <p>i am raising exception using</p>
  
  <pre><code>if UserId == '' and Password == '':
      raise Exception.MyException , "wrong userId or password" 
  </code></pre>
  
  <p>but i want print the error message on same page</p>
  
  <pre><code>class MyException(Exception):
      def __init__(self,msg):
          Exception.__init__(self,msg)
  </code></pre>