Alternative for update=False for dynet.parameter

I've used `dynet.parameter(regularization_term, update=False)` to accumulate a regularization term that should not be updated and to which I've added other penalty terms during a training step. `update=False` does no longer seem to work with the newest `dynet` version. How do I alternatively define a parameter that should not be updated? Is there a better way to define a regularizer in dynet?

Start by reproducing the reported dynet.parameter(regularization_term, update=False) usage against the current API and inspect how the update flag is handled. Compare the current behavior with the requested non-updated parameter and regularizer use; done means documenting or validating a supported alternative.

Written by the indexing model from the issue text.