message: Loose the check for BN when momentum == 0.
  Fix
diff: @@ -1615,13 +1615,8 @@ def fused_batch_norm(
  [Ioffe et al., 2015](http://proceedings.mlr.press/v37/ioffe15.html)
  ([pdf](http://proceedings.mlr.press/v37/ioffe15.pdf))
  """
  - if is_training and exponential_avg_factor == 1.0:
  - if (mean is not None) or (variance is not None):
  - raise ValueError("Both 'mean' and 'variance' must be None when "
  - "is_training is True and "
  - "exponential_avg_factor == 1.0.")
  - else:
  - if (mean is None) or (variance is None):
  + if (not is_training or exponential_avg_factor != 1.0) and (
  + (mean is None) or (variance is None)):
  raise ValueError("Both 'mean' and 'variance' must be a 1D tensor when "
  "is_training is False or "
  "exponential_avg_factor != 1.0.")
  