'**Arguments:**
bounds         QRectF with coordinates relative to view box. The default is QRectF(0,0,1,1),
which means the item will have the same bounds as the view.'

def __init__(self, bounds=None, parent=None):

    GraphicsObject.__init__(self, parent)
    self.setFlag(self.ItemSendsScenePositionChanges)
    if (bounds is None):
        self._bounds = QtCore.QRectF(0, 0, 1, 1)
    else:
        self._bounds = bounds
    self._boundingRect = None
    self._updateView()
