'Random draw of the measurement disturbance vector from its conditional
distribution.
Notes
.. math::
arepsilon ~ N(\hat arepsilon, Var(\hat arepsilon \mid Y_n))'

@property
def simulated_measurement_disturbance(self):

    if (self._simulated_measurement_disturbance is None):
        self._simulated_measurement_disturbance = np.array(self._simulation_smoother.simulated_measurement_disturbance, copy=True)
    return self._simulated_measurement_disturbance
