All paths from source to destination

graph = [[1, 3], [2], [3], []]

dest  = len(graph)-1

cache = {len(graph)-1: [[len(graph)-1]]}
def paths(start):
    if start in cache.keys():
        return cache[start]

    path = []
    for vertex in graph[start]:
        path+= [[start]+p for p in paths(vertex)]

    cache[start] = path
    return path

print(paths(0))