Dynamic addresses?

I am trying to build a face-edge graph from a model in STP form. Just as its name, the vertices of the graph are the faces of the model and the edge between 2 vertices are the edge between 2 adjacent faces. So I need to iterate over faces and edges of the model.

However, it seems that the addresses of the workplane objects are dynamic. When I print model.faces().all() for several times, the results are all different. Also, when I take an edge from a face, the edge is not likely to be in model.edges.all().