message: Clarify that min <= max is actually a requirement.
diff: @@ -42,6 +42,9 @@ def clip_by_value(t, clip_value_min, clip_value_max,
  Any values less than `clip_value_min` are set to `clip_value_min`. Any values
  greater than `clip_value_max` are set to `clip_value_max`.
  + Note: `clip_value_min` needs to be smaller or equal to `clip_value_max` for
  + correct results.
  +
  Args:
  t: A `Tensor`.
  clip_value_min: A 0-D (scalar) `Tensor`, or a `Tensor` with the same shape
  