The test function in SimpleDialog is named "test()" 
instead of "_test()".  Since it only is used to test the 
SimpleDialog class, at the very least it should be 
named "_test()" so it doesn't run the risk of overwriting 
a function by the same name when imported using "from 
SimpleDialog import *".

However, I propose that the function declaration for test
() be moved under "if __name__ == '__main__':", that 
way the function is explicitly not part of the SimpleDialog 
module.