title: How to call/run a method only one time in python
body: <p>I want to call/run a method only onetime I tried this but it didn't wotk:</p>
  
  <pre><code>class S ()
      _int_(self)
        self.xxx = True # i tried with and without
      def Packet (event):
         if (xxx == True):  
             self.f(event, xxx)
             print xxx
         else:
             ....
      def f (event):
         print "something"
         Do_Somthing
         xxx=False
  </code></pre>
  
  <p>the problem xxx is still true</p>
  
  <p>Best regards
  Amer</p>