### Tell us what’s happening:

My code would seem to match the syntax, I don’t understand how it keeps raising an unspecified error. Neither my original attempt (commented) nor the list comprehension were successful.

### 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
targets_to_print = [target if target else graph]
shortest_path(my_graph, 'A')
# User Editable Region
```

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### Challenge Information:

Learn Algorithm Design by Building a Shortest Path Algorithm - Step 49