code: public List<OWLObject> getOWLObjectListAttribute(String name, List<OWLObject> defaultValue) {
          List<OWLObject> result = getValue(owlObjectAttributes, name, defaultValue);
          return new ArrayList<OWLObject>(result);
      }
docs: Gets the {@link OWLObject} list value of an attribute.
  @param name The name of the attribute.  Not null.
  @param defaultValue The default value for the attribute.  May be null.  This value will be returned if this
  metadata object does not contain an {@link OWLObject} list value for the specified attribute name.
  @return Either the {@link OWLObject} list value of the attribute with the specified name, or the value specified by the defaultValue
  object if this metadata object does not contain an {@link OWLObject} list value for the specified attribute name.
  @throws NullPointerException if name is null.