title: Why j is always taking letter i from string 'kiwi'?
body: <pre><code>&gt;&gt;&gt; a={i:j for i in "abcd" for j in "kiwi"}
  &gt;&gt;&gt; a
  {'a': 'i', 'b': 'i', 'c': 'i', 'd': 'i'}
  &gt;&gt;&gt;
  </code></pre>
  
  <p>please explain how this output is coming. Why j is  alway taking i from string 'kiwi' and what does colon mean in set comprehension</p>