Return the property values for the class, with default values applied where needed.

def _get_property_values_with_defaults(self, classname, property_values):
        """Return the property values for the class, with default values applied where needed."""
        # To uphold OrientDB semantics, make a new dict with all property values set
        # to their default values, which are None if no default was set.
        # Then, overwrite its data with the supplied property values.
        final_values = self.get_default_property_values(classname)
        final_values.update(property_values)
        return final_values