Worked on new concept TableRequest.subst_user, needed for
lino.apps.dsbe.models.persons_by_user()to provide links to
lino.apps.dsbe.models.MyPersonsrequests for other users.
A little bug: TypeError “unbound method get_handle() must be called with Persons instance as first argument (got ExtUI instance instead)” in reports.py, line 615 when trying to return the choices for a ForeignKey to Person. Unit test