code: def forward(
      model: Model[FloatsXdT, FloatsXdT], X: FloatsXdT, is_train: bool
  ) -> Tuple[FloatsXdT, Callable]:
      Y = model.ops.sigmoid(X, inplace=False)
  
      def backprop(dY: FloatsXdT) -> FloatsXdT:
          return cast(
              FloatsXdT,
              dY
              * model.ops.dsigmoid(
                  Y, inplace=False
              ),  # type:ignore[operator]
          )
  
      return Y, backprop
  
imports: from typing import Callable, Tuple, TypeVar, cast
  from ..config import registry
  from ..model import Model
  from ..types import FloatsXdT
label_desc: Use image node_id 2 for calling a global function with example usage: forward(model, X, is_train) and returns: Y,  backprop, cast