def dijkstras(initial_node, destination_node, edge_set_by_node):
distances = {key: float('inf') for key in edge_set_by_node.keys()}
distances[initial_node] = 0
current_node = initial_node
visited = set()
to_visit = PriorityQueue(distances)
to_visit.add(current_node)
while not to_visit.empty and destination_node not in visited:
neighbors = edge_set_by_node[current_node]
current_distance = distances[current_node]
for neighbor in neighbors:
node = neighbor[0]
new_distance = current_distance + neighbor[1]
if node not in visited and distances[node] > new_distance:
distances[node] = new_distance
if node not in to_visit.nodes:
to_visit.add(node)
visited.add(current_node)
current_node = to_visit.get_next()
return distances[destination_node]
