|   | 1 |  initial version  | 
Note that this function was completely broken for any bipartite graph... not only trees. We have fixed it in the development version and should work fine with next Sage version (will be 8.4).
 Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.
 
                
                Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.