graf.
Node
Class for nodes within a C{Graph} instance. Each node keeps a list of in-edges and out-edges. Each collection is backed by two data structures: 1. A list (for traversals) 2. A hash map Nodes may also contain one or more C{Annotation} objects.
__init__
Constructor for C{GraphElement}.
add_region
Adds the given region to the first link for this node
clear
Clears this node’s visited status and those of all visited descendents