Ambiguous sentence in documentation

Hi,

I'm using graph-tool to do a simple astar search, and the documentation has the following sentence under astar_search:

heuristic : unary function (optional, default: lambda v: 1) The heuristic function that guides the search. It should take a single argument which is a Vertex, and output an estimated distance from the source vertex.

This is kind of ambiguous, because it is not clear which source vertex you are referring to. Is it the one which is passed to the original call? Or is the argument v === source vertex? (But I already know the answer)

Can I suggest the following wording? (changes bold)

heuristic : unary function (optional, default: lambda v: 1) The heuristic function that guides the search. It should take a single argument which is a Vertex, and output an estimated distance from the supplied vertex to the target vertex.