Heavily nested code is one of my bigger pet peeves. I’ve found that the more nesting there is in a block of code, the more likely it is that it’ll be confusing to follow. Here’s an example:

def something(request):
    if condition_a and condition_b and condition_c:
        lots
        more
        and_even_more
        etc
        if something_else:
            etc
            etc
            etc
        etc
        etc of code here
        return True
    else:
        return False

The “return False” is pretty far-removed from the set of conditions that will cause it to execute. An easy way to restructure this code (while still having the exact same functionality) would be to use the set of conditions as a guard:

def something(request):
    if not (condition_a and condition_b and condition_c):
        return False
 
    lots
    more
    and_even_more
    etc
    if something_else:
        etc
        etc
        etc
    etc
    etc of code here
    return True

Preemptive comment: I’m fully aware that some people feel very strongly about only having “single return point” for a function. I disagree. I’d rather minimize the number of return statements from a function, but in this case I think it adds clarity.