nested loops and goto line

[eddiefisher41]

Hello.
I have a quick question about loops, i just cant seem to get it to work correctly. the code generates a tuple containing a set of numbers. The if statement is designed to catch tuples that are not valid, if its not a valid one then i need it to go back to line 1 and regenerate the tuple.

def function():
............... ............... # line1
............... ............... # line2
............... ............... # line3
............... ............... # line4

if (logical statement = true):
goto line 4

Now rather than putting those 4 lines into another function and messing up my counter scheme id rather use some kind of loop structure.
I have tried using a while loop:

while (logical statement = true):
............... ............... # line1
............... ............... # line2
............... ............... # line3
............... ............... # line4

But this comes problematic when it needs to exit the loop and gives infinate loops, YUK!

Any help would be much appreciated.
Ed