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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 subplot(self, index_x, index_y):
 """ Sets the active subplot. Parameters index_x : int Index of the subplot to activate in the x direction. index_y : int Index of the subplot to activate in the y direction. """

        self._active_renderer_index = self.loc_to_index((index_x, index_y))