'Create a new stack widget.
:type canvas: Tkinter.Canvas
:param canvas: This canvas widget\'s canvas.
:param children: The widgets that should be aligned
vertically.  Each child must not have a parent.
:type children: list(CanvasWidget)
:param attribs: The new canvas widget\'s attributes.'

def __init__(self, canvas, *children, **attribs):

    self._align = 'center'
    self._space = 1
    self._ordered = False
    self._children = list(children)
    for child in children:
        self._add_child_widget(child)
    CanvasWidget.__init__(self, canvas, **attribs)
