def _advance_window(self):
x_to_remove, y_to_remove = self._x_in_window[<NUM_LIT:0>], self._y_in_window[<NUM_LIT:0>]<EOL>self._window_bound_lower += <NUM_LIT:1><EOL>self._update_values_in_window()<EOL>x_to_add, y_to_add = self._x_in_window[-<NUM_LIT:1>], self._y_in_window[-<NUM_LIT:1>]<EOL>self._remove_observation(x_to_remove, y_to_remove)<EOL>self._add_observation(x_to_add, y_to_add)<EOL>
Update values in current window and the current window means and variances.