message: Mark bfloat16 as trainable.
diff: @@ -30,4 +30,4 @@ def IsTrainable(tensor_or_dtype):
  dtype = dtypes.as_dtype(dtype)
  return dtype.base_dtype in (dtypes.float16, dtypes.float32, dtypes.float64,
  dtypes.complex64, dtypes.complex128,
  - dtypes.resource, dtypes.variant)
  + dtypes.resource, dtypes.variant, dtypes.bfloat16)
  