code: function _wildcardMatch(statusCode) {
      var match;
      Object.keys(opts.handlers).forEach(function (handlerStatusCode) {
        var regex = new RegExp(handlerStatusCode.replace(/x/g, '.'));
        if (!match && statusCode.toString().match(regex)) {
          match = handlerStatusCode;
        }
      });
      return match;
    }
docs: check for any wildcard match (e.g. 201 matches 2xx)