class_docstr: Retrieves the hidden tensor from a :class:`Portal`.
class_docstr_tok: ["Retrieves","the","hidden","tensor","from","a",":","class",":","`","Portal","`","."]
code: def backward(ctx: Context, grad: Tensor) -> Tuple[None, None]:  # type: ignore
      # The paired PortalBlue will use the gradient.
      ctx.portal.put_grad(grad)
      return None, None
  
imports: from typing import Any, List, Optional, Tuple
  import torch
  from torch import Tensor
  from .None import Namespace
  from ..copy import Context
  from ..copy import Copy
  from ..phony import get_phony
  from ..stream import AbstractStream, get_device
label_desc: Use image node_id 2 for calling the PortalOrange obj's underlying member method code with example usage: obj.backward(ctx, grad) and returns: None,  None