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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_mean_in_window(self):
 """ Compute mean in window the slow way. useful for first step. Considers all values in window See Also -------- _add_observation_to_means : fast update of mean for single observation addition _remove_observation_from_means : fast update of mean for single observation removal """

        self._mean_x_in_window = numpy.mean(self._x_in_window)
        self._mean_y_in_window = numpy.mean(self._y_in_window)