MultiProblem class for multitask learning.
MultiProblem class for multitask learning.

PiperOrigin-RevId: 202339795

tensorflow/tensor2tensor,vthorsteinsson/tensor2tensor,vthorsteinsson/tensor2tensor,tensorflow/tensor2tensor,tensorflow/tensor2tensor,tensorflow/tensor2tensor,vthorsteinsson/tensor2tensor,tensorflow/tensor2tensor,vthorsteinsson/tensor2tensor