code: def _apply_krauss(krauss: Union[Tuple[np.ndarray], Sequence[Any]],
          args: 'ApplyChannelArgs') -> np.ndarray:
      
      # Initialize output.
      args.out_buffer[:] = 0
      # Stash initial state into buffer0.
      np.copyto(dst=args.auxiliary_buffer0, src=args.target_tensor)
  
      # Special case for single-qubit operations.
      if krauss[0].shape == (2, 2):
          return _apply_krauss_single_qubit(krauss, args)
      # Fallback to np.einsum for the general case.
      return _apply_krauss_multi_qubit(krauss, args)
docs: Directly apply the kraus operators to the target tensor.