Networkx duplicate edges
You can test it pretty quickly, but it only adds them once. Edges and nodes are represented as a dictionaries inside the graph structure, and they are only added if they don't actually exist.
For already existing edges, adding them again has no effect.
If the same edge is added twice to the networkx edge data structure, will it then have two edges between the nodes or still just one? For example, would a spring layout show the nodes converge more with edges [(a,b),(a,b),(a,b),(a,b)] than [(a,b),(a,b)]? If I want to weight the edge, how would I go about it?