old_contents: var chart = {
    render: function(data){
      nv.addGraph(function() {
        var chart = nv.models.pieChart()
          .x(function(d) { return d.label })
          .y(function(d) { return d.value })
          .id(function(d) { return d.id })
          .showLabels(false);
        // Use integers in the values:
        chart.valueFormat(d3.format('d'));
  
        d3.select("#chart__stage svg")
          .datum(data.apps.stage)
          .transition().duration(350)
          .call(chart);
  
        d3.select("#chart__domain svg")
          .datum(data.apps.domain)
          .transition().duration(350)
          .call(chart);
  
        d3.select("#chart__feature svg")
          .datum(data.apps.feature)
          .transition().duration(350)
          .call(chart);
  
        d3.selectAll('.nv-slice')
          .on('click', function(d, i){
            console.log(d.data.url)
            window.location.href = d.data.url;
        });
  
        return chart;
      });
    }
  }
  
new_contents: var chart = {
    render: function(data){
      nv.addGraph(function() {
        var chart = nv.models.pieChart()
          .x(function(d) { return d.label })
          .y(function(d) { return d.value })
          .showLabels(false);
        // Use integers in the values:
        chart.valueFormat(d3.format('d'));
  
        d3.select("#chart__stage svg")
          .datum(data.apps.stage)
          .transition().duration(350)
          .call(chart);
  
        d3.select("#chart__domain svg")
          .datum(data.apps.domain)
          .transition().duration(350)
          .call(chart);
  
        d3.select("#chart__feature svg")
          .datum(data.apps.feature)
          .transition().duration(350)
          .call(chart);
  
        d3.selectAll('.nv-slice')
          .on('click', function(d, i){
            console.log(d.data.url)
            window.location.href = d.data.url;
        });
  
        return chart;
      });
    }
  };
  
subject: Remove non-used property.