code: function(key, reason) {
  			if (typeof key !== 'string') {
  				throw new Error('Incomplete data: key must be a string');
  			}
  			if (reason) {
  				data[key] = reason;
  			}
  			return data[key];
  		}
docs: Store incomplete data by key with a string value
  @method set
  @memberof axe.commons.color.incompleteData
  @instance
  @param {String} key Identifier for missing data point (fgColor, bgColor, etc.)
  @param {String} reason Missing data reason to match message template