title: Does dict.values() returns in an ordered sequence?
body: <pre><code>dict_mark = {'Wang': 'C', 'Li': 'B', 'Ma': 'A'}
  s = ''
  for c in dict_mark.values():
      s += c
  print(s)
  </code></pre>
  
  <p>dictionary is unordered,so why does <code>dict_mark.values()</code> always return this value sequence like <code>'C' 'B' 'A'</code>?</p>
  
  <p>Why not <code>'B' 'A' 'C'</code> or <code>'A' 'B' 'C'</code>? </p>