def _rename(self, node, name):
        '''
        Rename an internal node of the tree. If an annotation is already
        present, append the new annotation to the end of it. If a bootstrap
        value is present, add annotations are added after a ":" as per standard
        newick format.

        Parameters
        ----------
        node: dendropy.Node
            dendropy.Node object
        name    : string
            Annotation to rename the node with.
        '''
        if node.label:
            try:
                float(node.label)
                new_label = "%s:%s" % (node.label,
                                       name)
            except ValueError:
                new_label = "%s; %s" % (node.label,
                                        name)
            node.label = new_label
        else:
            node.label = name
Rename an internal node of the tree. If an annotation is already
        present, append the new annotation to the end of it. If a bootstrap
        value is present, add annotations are added after a ":" as per standard
        newick format.

        Parameters
        ----------
        node: dendropy.Node
            dendropy.Node object
        name    : string
            Annotation to rename the node with.