code: def fit_transform(self, X, y=None, **params):
          
          return self.fit(X, y).transform(X, y)
docs: Learn vocabulary and return document id matrix.
  
          This is equivalent to fit followed by transform.
  
          Args:
              X : iterable
              an iterable which yields either str, unicode or file objects.
  
          Returns:
              list : document id matrix.
              list: label id matrix.