def drawEdge(self, fromDrawNode, toDrawNode):
        for item in self.items():
            if type(item).__name__ != 'DrawEdge':
                continue
            if item.source == fromDrawNode and item.dest == toDrawNode:
                return item
        return None
Returns a drawEdge that links a given draw node to another given draw
dataset/ETHPy150Open andrew-gardner/dependsworkflow/depends/depends_graphics_widgets.py/SceneWidget.drawEdge