# Learn Algorithm Design by Building a Shortest Path Algorithm - Step 55

### Tell us what’s happening:

Hello, this question seems clear but I’m know why it tells me error. Please help tell errors In it

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

shortest_path(my_graph, 'A')

for node in targets_to_print:
print(f'\n{start}-{node} distance: {distances[node]}\nPath: {" -> ".join(paths[node])}')

# User Editable Region