title: Lists of lists in pandas.DataFrame constructor - an edge case?
body: <p>Here's where I run into trouble:</p>
  
  <pre><code>import pandas as pd
  df = pd.DataFrame( index = [1,3,5,7,11] )
  df['lists'] = [ ['a'],['b'],['c'],['a',b'],['a','b','c'] ]
  df['listOflists'] = [ [['a']], [['b'],['a']], [['c']], [['d']], [['e']] ]
  df['listOfLists1'] = [ [['a']], [['b']], [['a','c']], [['a','b','d']], [['e']] ]
  print df
  df['listOfLists_fails'] = [ [['a']], [['b']], [['a']], [['d']], [['e']] ]
  </code></pre>
  
  <p>The last example (only) throws an error in 0.11.0. One could get around this by assigning elementwise I suppose, but that seems ugly. Anyone know what is going on behind the scenes?  </p>