'Delete link(s) between node1 and node2
index: index of link to delete if multiple links (0)
allLinks: ignore index and delete all such links (False)
returns: deleted link(s)'

def delLinkBetween(self, node1, node2, index=0, allLinks=False):

    links = self.linksBetween(node1, node2)
    if (not allLinks):
        links = [links[index]]
    for link in links:
        self.delLink(link)
    return links
