message: Fix small typo on _tf_tensor_len
diff: @@ -140,7 +140,7 @@ def _tf_tensor_len(s):
  return s.shape.dims[0].value
  # Static shape of unknown dimensions: use dynamic shape but statically
  - # chech that it's a scalar.
  + # check that it's a scalar.
  shape = array_ops.shape(s)
  assert shape.shape, 'shape tensor of zero size? {}'.format(shape)
  