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}