what is it: graph': <graphs.graph_undirected at 0x13cf2d080>

[Sandy4321]

graph': <graphs.graph_undirected at 0x13cf2d080>,

may you explain
what is it: graph': <graphs.graph_undirected at 0x13cf2d080>,
https://structureboost.readthedocs.io/en/latest/feat_config.html