weights acts as a coefficient for the loss. If a scalar is provided,
then the loss is simply scaled by the given value. If weights is a
tensor of size [batch_size], then the loss weights apply to each
[batch_size, num_classes] logits outputs of the network .
[batch_size, 1] or [batch_size] labels of dtype int32 or int64
in the range [0, num_classes).
Coefficients for the loss. The tensor must be a scalar or a tensor
of shape [batch_size] or [batch_size, 1].
the scope for the operations performed in computing the loss.
A scalar Tensor representing the mean loss value.
If the shapes of logits, labels, and weights are
incompatible, or if weights is None.