title: '<' not supported between instances of 'tuple' and 'Version' error
body: <p>When I run the following code:</p>
  <pre class="lang-py prettyprint-override"><code>from sklearn.model_selection import train_test_split
  X_train, X_rest, y_train, y_rest = train_test_split(x, y, stratify=None,test_size=0.4)
  </code></pre>
  <p>I get this error:</p>
  <pre><code>--------------------------------------------------------------------------
  TypeError                                 Traceback (most recent call last)
  &lt;ipython-input-24-ade5fc6cc231&gt; in &lt;module&gt;
        3 #from sklearn.cross_validation import train_test_split
        4 
  ----&gt; 5 X_train, X_test, y_train, y_test = train_test_split(x, y, test_size=0.2, stratify=y, random_state=123, shuffle=True)
        6 
        7 # X_train, X_rest, y_train, y_rest = train_test_split(x, y, stratify=None,test_size=0.4)
  
  ~\anaconda3\lib\site-packages\sklearn\model_selection\_split.py in train_test_split(*arrays, **options)
     2152         train, test = next(cv.split(X=arrays[0], y=stratify))
     2153 
  -&gt; 2154     return list(chain.from_iterable((_safe_indexing(a, train),
     2155                                      _safe_indexing(a, test)) for a in arrays))
     2156 
  
  ~\anaconda3\lib\site-packages\sklearn\model_selection\_split.py in &lt;genexpr&gt;(.0)
     2152         train, test = next(cv.split(X=arrays[0], y=stratify))
     2153 
  -&gt; 2154     return list(chain.from_iterable((_safe_indexing(a, train),
     2155                                      _safe_indexing(a, test)) for a in arrays))
     2156 
  
  ~\anaconda3\lib\site-packages\sklearn\utils\__init__.py in _safe_indexing(X, indices, axis)
      393         return _pandas_indexing(X, indices, indices_dtype, axis=axis)
      394     elif hasattr(X, &quot;shape&quot;):
  --&gt; 395         return _array_indexing(X, indices, indices_dtype, axis=axis)
      396     else:
      397         return _list_indexing(X, indices, indices_dtype)
  
  ~\anaconda3\lib\site-packages\sklearn\utils\__init__.py in _array_indexing(array, key, key_dtype, axis)
      172 def _array_indexing(array, key, key_dtype, axis):
      173     &quot;&quot;&quot;Index an array or scipy.sparse consistently across NumPy version.&quot;&quot;&quot;
  --&gt; 174     if np_version &lt; parse_version('1.12') or issparse(array):
      175         # FIXME: Remove the check for NumPy when using &gt;= 1.12
      176         # check if we have an boolean array-likes to make the proper indexing
  
  TypeError: '&lt;' not supported between instances of 'tuple' and 'Version'
  </code></pre>