45.4. Sharing Data
  The global dictionary
  
   SD
  
  is available to store
   private data between repeated calls to the same function.
   The global dictionary
  
   GD
  
  is public data,
   that is available to all Python functions within a session;  use with
   care.
  
  
 
  Each function gets its own execution environment in the
   Python interpreter, so that global data and function arguments from
  
   myfunc
  
  are not available to
  
   myfunc2
  
  .  The exception is the data in the
  
   GD
  
  dictionary, as mentioned above.