UpgradeHelper

exception psi4.driver.UpgradeHelper(old, new, version, elaboration)

Error called on previously valid syntax that now isn’t and a simple syntax transition is possible.

It is much preferred to leave the old syntax valid for a release cycle and have the old syntax raise a deprecation FutureWarning. For cases where the syntax just has to jump, this can be used to trap the old syntax at first error and suggest the new.