code: function get(format) {
  		var ret;
  
  		// it's NaN if gradient colors on a column chart
  		if (rgba && !isNaN(rgba[0])) {
  			if (format === 'rgb') {
  				ret = 'rgb(' + rgba[0] + ',' + rgba[1] + ',' + rgba[2] + ')';
  			} else if (format === 'a') {
  				ret = rgba[3];
  			} else {
  				ret = 'rgba(' + rgba.join(',') + ')';
  			}
  		} else {
  			ret = input;
  		}
  		return ret;
  	}
docs: Return the color a specified format
  @param {String} format