具有多个tspan标签的jointjs形状中的文本重叠

var shape = new joint.shapes.basic.Rect({
    position: { x: 100, y: 100 },
    size: { width: 200, height: 100 },
    attrs: {
        rect: { fill: 'lightblue' },
        text: {
            text: [
                { text: 'Line 1', attrs: { 'tspan': { dy: '0em' } } },
                { text: 'Line 2', attrs: { 'tspan': { dy: '1em' } } },
                { text: 'Line 3', attrs: { 'tspan': { dy: '2em' } } }
            ]
        }
    }
});

var paper = new joint.dia.Paper({
    el: document.getElementById('paper'),
    model: new joint.dia.Graph(),
    width: 800,
    height: 600
});

paper.model.addCell(shape);