code: def forward(
      model: Model[InOutT, InOutT], X: InOutT, is_train: bool
  ) -> Tuple[InOutT, Callable]:
      def backprop(dY: InOutT) -> InOutT:
          return dY
  
      return X, backprop
  
imports: from typing import Callable, Tuple, TypeVar
  from ..config import registry
  from ..model import Model
label_desc: Use image node_id 2 for calling a global function with example usage: forward(model, X, is_train) and returns: X,  backprop, dY