Save a pickled version of the embedding into `fname`.

def save(self, fname):
    """Save a pickled version of the embedding into `fname`."""

    vec = self.vectors
    voc = self.vocabulary.getstate()
    state = (voc, vec)
    with open(fname, 'wb') as f:
      pickle.dump(state, f, protocol=pickle.HIGHEST_PROTOCOL)