Bug in get_distance() with flag topology_only=True in ete3

[lenacoll]

tree.get_distance(target, target2, topology_only=True) should (according to the documentation) return the number of nodes connecting target and target2. It does not correctly do this, as shown in this example:

tree = Tree("((A,B), C);")
node2 = tree.get_common_ancestor("A", "B")

Then:

tree.get_distance(tree, node2, topology_only=True)

1.0

tree.get_distance(node2, tree, topology_only=True)

0.0