Arbitrary Tree Data Structure.

class TreeWrapper: # subclass for a tree type
def children(self, treenode):
assert 0, 'children method must be specialized for tree type'
def label(self, treenode):
assert 0, 'label method must be specialized for tree type'
def value(self, treenode):
return ''
def onClick(self, treenode): # node label click callback
return ''
def onInputLine(self, line, viewer): # input line sent callback
pass