code: function brushDataAdapter(dataLine) {
      return dataLine.dataByDate.map(function(d){
          d.value = d.topics.reduce(function(acc, topic) {
              return acc + topic.value;
          },0);
  
          return d;
      })
  }
docs: /*
  The Brush chart wants an input like this one
  @example
  [
  {
  value: 1,
  date: '2011-01-06T00:00:00Z'
  },
  {
  value: 2,
  date: '2011-01-07T00:00:00Z'
  }
  ]