old_contents: 
  var co = require('..');
  var fs = require('fs');
  
  function size(file) {
    return function(fn){
      fs.stat(file, function(err, stat){
        if (err) return fn(err);
        fn(null, stat.size);
      });
    }
  }
  
  var foo = co(function *(){
    var a = yield size('.gitignore');
    var b = yield size('Makefile');
    var c = yield size('package.json');
    return [a, b, c];
  })
  
  var bar = co(function *(){
    var a = yield size('examples/parallel.js');
    var b = yield size('examples/nested.js');
    var c = yield size('examples/simple.js');
    return [a, b, c];
  })
  
  co(function *(){
    var a = yield foo;
    var b = yield bar;
    console.log(a);
    console.log(b);
  })
  
new_contents: 
  var co = require('..');
  var fs = require('fs');
  
  function size(file) {
    return function(fn){
      fs.stat(file, function(err, stat){
        if (err) return fn(err);
        fn(null, stat.size);
      });
    }
  }
  
  var foo = co(function *(){
    var a = yield size('.gitignore');
    var b = yield size('Makefile');
    var c = yield size('package.json');
    return [a, b, c];
  })
  
  var bar = co(function *(){
    var a = yield size('examples/return.js');
    var b = yield size('examples/nested.js');
    var c = yield size('examples/simple.js');
    return [a, b, c];
  })
  
  co(function *(){
    var a = yield foo;
    var b = yield bar;
    console.log(a);
    console.log(b);
  })
  
subject: fix example