code: def encode_i64_vec(self, vec: torch.Tensor):
      vec = vec.detach().flatten()
      return self.coder.encode_u64_vec(
          vec.detach().numpy().astype("uint64")
      )
  
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 15 for calling the Coder obj's underlying member method code with example usage: obj.encode_i64_vec(vec) and returns: self