Before SCH-level objects can be stuck in the undo/redo memento,
we need to remove all "live" references such as NodeProxies for
nodes in the current instantiation of the graph.
Interp -
Static variable in class story.dbcore.nodes.NodeType
INTERP -
Static variable in class story.scheherazade.elements.StateTime
A snapshot of what closure is missing from the interp part of the
story graph, that is keeping the graph from fulfilling the
theoretical model of a closed graph.