def klass_from_predicate(predicate)
      field_name = field_from_predicate(predicate)
      return unless field_name

      relation = relations[field_name]
      return unless relation

      relation.class_name.constantize
    end
def klass_from_predicate(predicate)
      field_name = field_from_predicate(predicate)
      return unless field_name

      relation = relations[field_name]
      return unless relation

      relation.class_name.constantize
    end
Retrieve the class for a relation, based on its defined RDF predicate

 @param [RDF::URI] predicate a URI for the RDF::Term
 @return [Ladder::Resource, Ladder::File, nil] related class