text: """
  Utility functions for Gaussian filtering and smoothing.
  """
  
  from probnum.filtsmooth.statespace import ContinuousModel, DiscreteModel
  
  
  def is_cont_disc(dynamod, measmod):
      """Checks whether the state space model is continuous-discrete."""
      dyna_is_cont = isinstance(dynamod, ContinuousModel)
      meas_is_disc = isinstance(measmod, DiscreteModel)
      return dyna_is_cont and meas_is_disc
  
  
  def is_disc_disc(dynamod, measmod):
      """Checks whether the state space model is discrete-discrete."""
      dyna_is_disc = isinstance(dynamod, DiscreteModel)
      meas_is_disc = isinstance(measmod, DiscreteModel)
      return dyna_is_disc and meas_is_disc
  