You are given the `length` and `width` of a 4-sided polygon. The polygon can either be a rectangle or a square. 
If it is a square, return its area. If it is a rectangle, return its perimeter.
```
area_or_perimeter(6, 10) --> 32
area_or_perimeter(4, 4) --> 16
```
> Note: for the purposes of this kata you will assume that it is a square if its `length` and `width` are equal, otherwise it is a rectangle.
def area_or_perimeter(l , w):
    if l == w:
        return l * w
    else:
        x = l*2
        y = w*2
        z = x + y
        return z
def area_or_perimeter(l , w):
    if l == w:
        return l * w
    else:
        x = l*2
        y = w*2
        z = x + y
        return z