title: For loops in a dictionary and if statement
body: <p>Firstly, I have to say that i'm a beginner in python.
  Then, here is my problem :
  I have a dictionary like this one :</p>
  
  <pre><code>dic = {} 
  dic["a", 1] = 0 
  dic["a", 2] = 2 
  dic["b", 1] = 5 
  dic["b", 2] = 0 
  ... 
  </code></pre>
  
  <p>And I want to do a for-loop with this dictionary to test all the keys' pair and find which ones are equivalent to 0 in a if statement.
  I thought of that :</p>
  
  <pre><code>for [co, l], ch in dic.items(): 
      if [co, l] == 0: 
  </code></pre>
  
  <p>But the if statement is never true, so I can't do anything.
  Does anyone could provide me some help, please ?</p>
  
  <p>Thanks</p>