In the current 1.5.1 the required parameter looks like it is supported
for all properties and there is a:


      def get_required_props(self, propnames = []):
        """Return a dict of property names mapping to property objects.
        All properties that have the "required" flag set will be
        returned in addition to all properties in the propnames
        parameter.
        """
 
in roundup/hyperdb.py::Class

So that could be of use here as well to get the default list of
properties. I wonder if we also need to extend this to allow an array of
properties that should be removed:

      def get_required_props(self, propnames = [], filter = []):

where the props listed in filter will not be returned.
This could be useful if used for detectors.