code: function handle (fn) {
  	return function (...args) {
  		return new Promise((resolve) => {
  			fn.bind(this)(...args, function (err, result) {
  				/* istanbul ignore if */
  				if (err) {
  					debug(err);
  				} else {
  					resolve(result);
  				}
  			});
  		});
  	};
  }
docs: If an error happes send it to debug function.