How to use the jsplumb.getInstance function in jsplumb

let DependenciesManager = function (gantt, pluginScope, api) {
    let self = this

    this.gantt = gantt
    this.pluginScope = pluginScope
    this.api = api

    this.api.registerEvent('dependencies', 'add')
    this.api.registerEvent('dependencies', 'change')
    this.api.registerEvent('dependencies', 'remove')

    this.plumb = jsplumb.jsPlumb ? jsplumb.jsPlumb.getInstance() : jsplumb.getInstance() // Workaround for build issue.
    this.plumb.importDefaults(this.pluginScope.jsPlumbDefaults)

    this.dependenciesFrom = {}
    this.dependenciesTo = {}

    this.tasksList = []
    this.tasks = {}

    this.events = new GanttDependenciesEvents(this)

    this.pluginScope.$watch('enabled', function (newValue, oldValue) {
      if (newValue !== oldValue) {
        self.refresh()
      }
    })

connect: function() {
            const chartOptions = _.defaults({
                container: this.id()
            }, this.defaultsChartOptions);
            this.jsPlumbInstance = jsPlumb.getInstance(chartOptions);
            this.jsPlumbInstance.eventBus = Object.create(Backbone.Events);
            if (this.chartHandlers) {
                this.listenTo(this.jsPlumbInstance.eventBus, this.chartHandlers);
            }
            this.debouncedRepaintEverything = _.debounce(this.repaintEverything.bind(this), 0);
            this.jsPlumbManager = new JPManager(this.jsPlumbInstance, this.model);
            const stepWithPosition = this.model.get('steps').find(function(step) {
                const position = step.get('position');
                return _.isArray(position) && position.length === 2;
            });
            // if positions of step wasn't defined
            if (_.isUndefined(stepWithPosition)) {
                this.jsPlumbManager.organizeBlocks();
            }
        },

ret = parseInt(hint_anns[0].value());
	    //ll('extracted coord ' + x_or_y + ': ' + ret);
	}else if( hint_anns.length === 0 ){
	    //ll('no coord');
	}else{
	    //ll('too many coord');
	}

	return ret;
    }

    ///
    /// jsPlumb preamble.
    ///

    var instance = jsPlumb.getInstance(
	{
	    // All connections have these properties.
	    DragOptions: {ccursor: 'pointer', zIndex:2000 },
            Endpoints : ["Rectangle", ["Dot", { radius:8 } ]],
            //Endpoints : [["Dot", { radius:8 } ], "Rectangle"],
	    EndpointStyles : [
		{
		    width: 15,
		    height: 15,
		    //strokeStyle: '#000000',
		    fillStyle: "#666666"  // subject endpoint color
		},
		{
		    fillStyle: "#0d78bc" // object endpoint
		    //fillStyle: "#006"
		}