 public class XMLFileStore : SOGraphDBStore {
 
     open let xmlFileURL : URL
-    var nodeList = [Node]()
-    var relationshipList = [Relationship]()
     
     //MARK:  -
     

    
    //MARK: - Node
    
    public func register(_ aNode: Node) {
    }
    
    public func update(_ aNode: Node) {
        // TODO
    }
    
    public func delete(_ aNode: Node) {
        // TODO
    }
    
    //MARK: - Relationship
    
    public func register(_ aRelationship: Relationship) {
        // TODO
    }
    
    public func delete(_ aRelationship: Relationship) {
        // TODO
    }
    
    public func findRelationship(from startNode: Node, to endNode: Node) -> Relationship?{

        return nil
    }
    
     //MARK: - Persistent
    

    func readXMLFile() throws {
        
        //var error : NSError?
        
