code: function (keyOrNsString/*, type{String|Function}...*/) {
                  sjl.throwTypeErrorIfNotOfType(contextName + '.has', 'keyOrNsString', keyOrNsString, String);
                  var searchResult = sjl.searchObj(keyOrNsString, this);
                  return arguments.length === 1 ?
                      sjl.isset(searchResult) :
                      sjl.issetAndOfType.apply(sjl, [searchResult].concat(sjl.restArgs(1)));
              }
docs: Checks if a defined value exists for key (or namespace key) and returns it.
  If no value is found (key/ns-key is undefined) then returns undefined.
  @method sjl.stdlib.Config#has
  @param keyOrNsString {String}
  @returns {*|undefined}