Finds and returns a node in a graph corresponding to an item.
capi
find-graph-node graph object => node
graph
A graph-pane.
object
An item in graph .
node
A node of graph , or nil .
nil
The generic function find-graph-node finds the node that corresponds to the item object .
find-graph-node
If there is no such node, find-graph-node returns nil .
find-graph-edge graph-pane