<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def updateMesh(self, polydata):
 """ Overwrite the polygonal mesh of the actor with a new one. """

        self.poly = polydata
        self.mapper.SetInputData(polydata)
        self.mapper.Modified()
        return self