private function createGraph()
{
$this->client->run('MATCH (n) DETACH DELETE n');
$query = 'CREATE (john:User {name:"John"})-[:FRIEND]->(judith:User {name:"Judith"}),
(john)-[:FRIEND]->(paul:User {name:"paul"}),
(paul)-[:FRIEND]->(marc:User {name:"marc"}),
(paul)-[:FRIEND]->(bill:User {name:"Bill"}),
(judith)-[:FRIEND]->(bill),
(judith)-[:FRIEND]->(sofia),
(john)-[:FRIEND]->(sofia),
(sofia)-[:FRIEND]->(:User {name:"Zoe"})';
$this->client->run($query);
}