Line completion with custom commands

[gu]

Hi, my Python program can be launched with a range of different options 
(or subcommands) like:

$ myProgram doSomething
$ myProgram doSomethingElse
$ myProgram nowDoSomethingDifferent

I want it to use auto-completion with so that if i type "myProgram d" it 
returns "myProgram doSomething" and if i type "myProgram n" it renders 
"myProgram nowDoSomethingDifferent". This is similar to the average use 
of the module rlcompleter, but it does not pick possible completion 
options from the filesystem (or from history) but from a custom set of 
strings (that correspond to the available options for my program)

Any idea on how to implement this?

I'm aware of the variable PYTHONSTARTUP (that should point to a file I 
don't know how to write).

As a working example, django-admin (from the django package) has the 
same exact feature i'm looking for