function lib$es6$promise$polyfill$$polyfill() {
      var local;

      if (typeof global !== 'undefined') {
          local = global;
      } else if (typeof self !== 'undefined') {
          local = self;
      } else {
          try {
              local = Function('return this')();
          } catch (e) {
              throw new Error('polyfill failed because global object is unavailable in this environment');
          }
      }

      var P = local.Promise;

      if (P && Object.prototype.toString.call(P.resolve()) === '[object Promise]' && !P.cast) {
        return;
      }

      local.Promise = lib$es6$promise$promise$$default;
    }
`catch` is simply sugar for `then(undefined, onRejection)` which makes it the same
      as the catch block of a try/catch statement.

      ```js
      function findAuthor(){
        throw new Error('couldn't find that author');
      }

      // synchronous
      try {
        findAuthor();
      } catch(reason) {
        // something went wrong
      }

      // async with promises
      findAuthor().catch(function(reason){
        // something went wrong
      });
      ```

      @method catch
      @param {Function} onRejection
      Useful for tooling.
      @return {Promise}