code: function(code, callback) {
  		if (typeof code == 'function') {
  			callback = code;
  			this.promises.push(function onGenericStatusCode(done, utils) {
  				done(null, callback(this.scraper.getStatusCode(), utils));
  			});
  		} else {
  			this.promises.push(function onStatusCode(done, utils) {
  				if (code === this.scraper.getStatusCode()) {
  					done(null, callback(utils));
  				} else {
  					done(null, utils.lastReturn);
  				}
  
  			});
  		}
  		return this;
  	}
docs: Sets a promise for a status code, of a response of a request.
  
  @param  {!(number|function(number))} code Status code to
  dispatch the message. Or a callback function, in this case
  the function's first parameter is the status code, as a
  number.
  @param  {!function()} callback Callback function for the case
  where the status code is provided.
  @return {!ScraperPromise} This object, so that new promises can
  be made.
  @public