I attached resulting index.py.
oops, I attached wrong file, sorry.
Now is correct one.
import pyjd
from pyjamas.ui.Tree import Tree
from pyjamas.ui.TreeItem import TreeItem
from pyjamas.ui.RootPanel import RootPanel
def main():
pyjd.setup("http://localhost:8080/public/index.html")
tree = Tree()
s1 = TreeItem("Section 1")
s1.addItem(TreeItem("Item 1.1"))
s1.addItem(TreeItem("Item 1.2"))
s2 = TreeItem("Section 2")
s2.addItem(TreeItem("Item 2.1"))
s2.addItem(TreeItem("Item 2.2"))
tree.addItem(s1)
tree.addItem(s2)
RootPanel().add(tree)
pyjd.run()
main()