Learn Algorithm Design by Building a Shortest Path Algorithm - Step 57

Tell us what’s happening:

I’m struggling to figure out where the return() goes in this step. I’ve tried it in the for loop, in the function, and outside everything, and it doesn’t pass. Am I missing something about the return function, or is it something in the white space. Thanks!

Your code so far

my_graph = {
    'A': [('B', 3), ('D', 1)],
    'B': [('A', 3), ('C', 4)],
    'C': [('B', 4), ('D', 7)],
    'D': [('A', 1), ('C', 7)]
}

def shortest_path(graph, start, target = ''):
    unvisited = list(graph)
    distances = {node: 0 if node == start else float('inf') for node in graph}
    paths = {node: [] for node in graph}
    paths[start].append(start)
    
    while unvisited:
        current = min(unvisited, key=distances.get)
        for node, distance in graph[current]:
            if distance + distances[current] < distances[node]:
                distances[node] = distance + distances[current]
                if paths[node] and paths[node][-1] == node:
                    paths[node] = paths[current][:]
                else:
                    paths[node].extend(paths[current])
                paths[node].append(node)
        unvisited.remove(current)

# User Editable Region

    targets_to_print = [target] if target else graph
    for node in targets_to_print:
        if node == start:
            continue
        print(f'\n{start}-{node} distance: {distances[node]}\nPath: {" -> ".join(paths[node])}')
    return(distances, paths)
        
    
shortest_path(my_graph, 'A')

# User Editable Region

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Challenge Information:

Learn Algorithm Design by Building a Shortest Path Algorithm - Step 57

Hello and welcome to our forum.

Removing the brackets would solve the issue, but I can’t see the other error. But, if you reset the lesson and then run the return statement without the brackets, your code should pass. Can you try this one and then if it fails, I’ll do a more comprehensive check.