def interjoint_paths(self):
    """
    Returns paths between the adjacent critical points
    in the skeleton, where a critical point is the set of
    terminal and branch points.
    """
    paths = []
    for tree in self.components():
      subpaths = self._single_tree_interjoint_paths(tree)
      paths.extend(subpaths)

    return paths
Returns paths between the adjacent critical points
    in the skeleton, where a critical point is the set of
    terminal and branch points.