title: 'file' object has no attribute 'rfind'
body: <p>I am trying to save a word2vec to a file.</p>
  
  <pre><code>model = Word2Vec(sentences, size=vector_size, window=5, min_count=5, workers=4)
  fo = open("foo.txt", "wb")
  model.save(fo)
  </code></pre>
  
  <p>I am getting the following error in genericpath.py</p>
  
  <pre><code>File "word2Vec_impl.py", line 39, in &lt;module&gt;
  model.save(fo, separately=None)
  File "C:\Python27\lib\site-packages\gensim\models\word2vec.py", line 669, in s
  ave
  super(Word2Vec, self).save(*args, **kwargs)
  File "C:\Python27\lib\site-packages\gensim\utils.py", line 269, in save
  pickle(self, fname)
  File "C:\Python27\lib\site-packages\gensim\utils.py", line 608, in pickle
  with smart_open(fname, 'wb') as fout: # 'b' for binary, needed on Windows
  File "C:\Python27\lib\site-packages\gensim\utils.py", line 596, in smart_open
  _, ext = path.splitext(fname)
  File "C:\Python27\lib\ntpath.py", line 190, in splitext
  return genericpath._splitext(p, sep, altsep, extsep)
  File "C:\Python27\lib\genericpath.py", line 91, in _splitext
  sepIndex = p.rfind(sep)
  AttributeError: 'file' object has no attribute 'rfind'
  </code></pre>
  
  <p>Where I am going wrong?</p>