Converts given inputs from ragged tensors to dense tensors.

labels A tf.RaggedTensor of the same shape as predictions representing relevance.
predictions A tf.RaggedTensor with shape [batch_size, (list_size)]. Each value is the ranking score of the corresponding example.
weights An optional tf.RaggedTensor of the same shape of predictions or a tf.Tensor of shape [batch_size, 1]. The former case is per-example and the latter case is per-list.

A tuple (labels, predictions, weights, mask) of dense tf.Tensors.