When $H$ has multiple edges, and we ask whether it is a minor of another graph $G$, using the method:
G.minor(H)
the multiple edges are ignored. As a result, it can return True, when $H$ is not actually a minor of $G$.
Here is a small example of this incorrect behavior.
Let $H$ be a triangle with a double edge, and let $G$ be a square. Clearly, $H$ is not a minor of $G$.
H = Graph()
H.allow_multiple_edges(True)
H.add_edges([(0,1), (0,1), (0,2), (1,2)])
G = Graph()
G.allow_multiple_edges(True)
G.add_edges([(0,1), (0,3), (1,2), (2,3)])
G.minor(H)
The output is:
{0: [0], 1: [1], 2: [2, 3]}
Is there a work-around?
