rmatter: function(min, precision) { // callback function that formats the min y value label
   *     return parseFloat(min).toFixed(precision);
   *   },
   *   yMaxFormatter: function(max, precision) { // callback function that formats the max y value label
   *     return parseFloat(max).toFixed(precision);
   *   },
   *   maxDataSetLength: 2,
   *   interpolation: 'bezier'                   // one of 'bezier', 'linear', or 'step'
   *   timestampFormatter: null,                 // optional function to f