function test_resource_is_first_list()
 {
     $Graph = new PueliaGraph(file_get_contents('documents/test-data.ttl'));
     $parentLists = $Graph->get_subjects_where_resource(RDF_REST, '_:lastList');
     $this->assertFalse($Graph->resource_is_first_list('_:lastList'), "should return false because list is linked to from another list");
     $this->assertTrue($Graph->resource_is_first_list('_:itemsList'), "should return true because list is not rdf:rest of any other list");
 }