743 refactor usages of graph
Created by: maypink
Refactor Graph (& OptGraph) usages:
- Now
graph.operator
can not be used outside of graph - Remove direct usaged of
graph.nodes
: now there is a private field_nodes
and propertynodes
. However users can still modify nodes using this property - Some methods (
sort_nodes
andactualise_old_node_children
) were not moved to graph interface since they are not in use anywhere