title: Best way to check if an item is present in a list of lists?
body: <p>I have example list like this:</p>
  
  <pre><code>example_list = [['aaa'], ['fff', 'gg'], ['ff'], ['', 'gg']]
  </code></pre>
  
  <p>Now, I check if it has empty string like this:</p>
  
  <pre><code>has_empty = False;
  for list1 in example_list:
      for val1 in list1:
          if val1 == '':
              has_empty = True
  
  print(has_empty)
  </code></pre>
  
  <p>This works OK as it prints True, but looking for more pythonik method? </p>