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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def dummyctrl(self,r,ctrl):
 """creates a DummyVertex at rank r inserted in the ctrl dict of the associated edge and layer. Arguments: r (int):
 rank value ctrl (dict):
 the edge's control vertices Returns: DummyVertex : the created DummyVertex. """

        dv = DummyVertex(r)
        dv.view.w,dv.view.h=self.dw,self.dh
        self.grx[dv] = dv
        dv.ctrl = ctrl
        ctrl[r] = dv
        self.layers[r].append(dv)
        return dv