title: Can the mob function in partykit build model trees using regularized linear models, such as ridge regression?
body: <p>Is it possible to correctly use regularized linear or generalized linear models with the <strong>mob</strong> function in partykit?</p>
  
  <p>I imagine the null hypothesis of the parameter stability tests that partykit uses would need to change to a non-standard Brownian Bridge because the score function is no longer 0 on the full set of data points, but rather shifted by the gradient of the penalizing term.</p>