Changes during run

[Thomas Thiele]

I have a program in which a function is called. For instance by pressing
on a button (Tkinter).

in mainframe class:

def ButtonPressed(self):
	self.Function()


def Function(Self):
	a = 5
	print a


I start the program and all things work great. Only the function
Function is wrong (I wrote a = 5 instead of a = 6 ).
Is it possible to correct the function without restarting the program?

I start the program and press the button. I see a is 5. 
I correct the source code (replace 5 with 6) and press the button again.
And now I want to see that 6 is printed. 

Is this possible? That would be really rapid prototyping!

Thomas