weight :: WeightedGraph -> (Vertex, Vertex) -> Maybe Float
weight (LGraph _ labels) (s,d) =
  lookup (s,d) labels
weight :: WeightedGraph -> (Vertex, Vertex) -> Maybe Float
weight (LGraph _ labels) (s,d) =
  lookup (s,d) labels
weight (LGraph _ labels) (s,d) =
  lookup (s,d) labels