title: python shared dictionary using ray?
body: <p>Reading Ray <a href="https://ray.readthedocs.io/en/latest/serialization.html" rel="nofollow noreferrer">docs</a> I see it supports serialization of <code>dicts</code> natively ("Serialize directly"),
  But I cannot understand what that means, Or what should I do to use those serialized objects.<br>
  Given that I have the following flow:</p>
  
  <pre><code>import ray
  ray.init()
  
  dict_1 = {}
  dict_2 = {}
  
  @ray.remote
  def f(x):
      dict_1[x] = x*x
      dict_2[x] = x*x*x
      return x
  
  futures = [f.remote(i) for i in range(4)]
  print(ray.get(futures))
  </code></pre>
  
  <p>Should I do something to gureentee thread-safe behaviour?</p>