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