text: export default {
      x: {
          type: 'linear',
          column: 'Sepal.Length',
          bin: 15
      },
      y: {
          type: 'linear',
          behavior: 'flex',
          domain: [0]
      },
      marks: [
          {
              type: 'bar',
              per: ['Sepal.Length'],
              summarizeY: 'count'
          }
      ]
  };
  