def set_XY(self, X, Y):
self.update_model(False)<EOL>self.set_Y(Y)<EOL>self.set_X(X)<EOL>self.update_model(True)<EOL>
Set the input / output data of the model
This is useful if we wish to change our existing data but maintain the same model

:param X: input observations
:type X: np.ndarray
:param Y: output observations
:type Y: np.ndarray or ObsAr