Not sure why this while loop is not accepted

### 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)]
}
# User Editable Region
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 len(unvisited) != 0:
pass
print(f'Unvisited: {unvisited}\nDistances: {distances}\nPaths: {paths}')
#shortest_path(my_graph, 'A')
# User Editable Region
```

### Your browser information:

User Agent is: `Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36`

### Challenge Information:

Learn Algorithm Design by Building a Shortest Path Algorithm - Step 34