def _group_tree_branch(root_group, highlight_group_name=None, children=[]):
'''Returns a branch of the group tree hierarchy, rooted in the given group.
:param root_group_id: group object at the top of the part of the tree
:param highlight_group_name: group name that is to be flagged 'highlighted'
:returns: the top GroupTreeNode of the tree
'''
nodes = {} # group_id: GroupTreeNode()
root_node = nodes[root_group.id] = GroupTreeNode(
{'id': root_group.id,
'name': root_group.name,
'title': root_group.title,
'dataset_count': root_group.subtree_dataset_count})
root_node.update(root_group.custom_extras)
if root_group.name == highlight_group_name:
nodes[root_group.id].highlight()
highlight_group_name = None
for group_id, group_name, group_title, parent_id, dataset_count, extras in children:
node = GroupTreeNode({'id': group_id,
'name': group_name,
'title': group_title,
'dataset_count': dataset_count})
if extras:
node.update(extras)
nodes[parent_id].add_child_node(node)
if highlight_group_name and group_name == highlight_group_name:
node.highlight()
nodes[group_id] = node
return root_node
