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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 update_devices(self, selection=None):
 """Determines the order, in which the |Node| and |Element| objects currently handled by the |HydPy| objects need to be processed during a simulation time step. Optionally, a |Selection| object for defining new |Node| and |Element| objects can be passed."""

        if selection is not None:
            self.nodes = selection.nodes
            self.elements = selection.elements
        self._update_deviceorder()