title: Iterate over Dictionary: Get 'NoneType" object is not iterable error
body: <p>The function class:</p>
  
  <pre><code>def play_best_hand(hand, wordDict):
  
  tempHand = hand.copy()
  points = 0
  for word in wordDict:
      for letter in word:
          if letter in hand:
              tempHand[letter] = tempHand[letter] - 1 
              if tempHand[letter] &lt; 0:
                  return False
              if wordDict[word] &gt; points:
                  bestWord == word
                  points = wordDict[word]
  return bestWord
  </code></pre>
  
  <p>Here is my trackback error.  Line 209 corresponds to the line 'for word in wordDict'</p>
  
  <pre><code> Traceback (most recent call last):
      File "ps6.py", line 323, in &lt;module&gt;
      play_game(word_list)
    File "ps6.py", line 307, in play_game
      play_hand(hand.copy(), word_list)
    File "ps6.py", line 257, in play_hand
      guess = play_best_hand(hand, wordDict)
    File "ps6.py", line 209, in play_best_hand
      for word in wordDict:
  TypeError: 'NoneType' object is not iterable
  </code></pre>