Merge Sort - the Pythonic way

merge_sort.py

def sort(l):
    if len(l) <= 1:
        return l
    mid = len(l) // 2
    return merge(sort(l[:mid]), sort(l[mid:]))

def merge(l, r):
    out = []
    while l and r:
        if l[0] <= r[0]:
            out.append(l.pop(0))
        else:
            out.append(r.pop(0))
    out.extend(l)
    out.extend(r)
    return out

def main():
    l = [3, 2, 5, 1, 4]
    print(sort(l))

if __name__ == "__main__":
    main()