# Learn Algorithm Design by Building a Shortest Path Algorithm - Step 42

### Tell us what’s happening:

perhaps my syntax with extend() is wrong?

``````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):
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]

/* User Editable Region */

if paths[node][-1] == node:
paths[node] = paths[current]
else:
paths[node].extend(current)

/* User Editable Region */

print(f'Unvisited: {unvisited}\nDistances: {distances}\nPaths: {paths}')

#shortest_path(my_graph, 'A')

``````

User Agent is: `Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36`

### Challenge Information:

Learn Algorithm Design by Building a Shortest Path Algorithm - Step 42

How do you access the current node path? You’ve done this already in the previous line

1 Like

Hello! @lswoboda051

You’re almost there!

The else condition needs to be modified `(paths[current])` must be the argument inside the extend() function.

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