':type node:
:type subtrees: list(CanvasWidgetI)'

def __init__(self, canvas, label, subtrees, **attribs):

    self._label = label
    self._subtrees = subtrees
    self._horizontal = 0
    self._roof = 0
    self._xspace = 10
    self._yspace = 15
    self._ordered = False
    self._lines = [canvas.create_line(0, 0, 0, 0, fill='#006060') for c in subtrees]
    self._polygon = canvas.create_polygon(0, 0, fill='', state='hidden', outline='#006060')
    self._add_child_widget(label)
    for subtree in subtrees:
        self._add_child_widget(subtree)
    self._managing = False
    CanvasWidget.__init__(self, canvas, **attribs)
