code: def unpack_vec(
      self, vec: FV, num_shift_bit, num_elem_each_pack, total_num
  ) -> torch.LongTensor:
      return torch.LongTensor(
          self.coder.unpack_u64_vec(
              vec, num_shift_bit, num_elem_each_pack, total_num
          )
      )
  
imports: from typing import List, Optional, Tuple
  import torch
  from fate_utils.ou import CiphertextVector, PlaintextVector
  from fate_utils.ou import Coder
  from fate_utils.ou import Evaluator
  from fate_utils.ou import PK
  from fate_utils.ou import SK
  from fate_utils.ou import keygen
  from .type import TensorEvaluator
label_desc: Use image node_id 5 for calling the Coder obj's underlying member method code with example usage: obj.unpack_vec(vec, num_shift_bit, num_elem_each_pack, total_num) and returns: torch