This condition is signaled when a vertex can not be found in an edge.
This is the root condition for graph errors that have to do with edges.
The `edge` that is implicated in the condition.Initargs::edge; Reader:edge.
The `graph` of which this edge is a part.Initargs::graph; Reader:graph.
The vertex or value that could not be found in the graph.Initargs::vertex; Reader:vertex.