docstr: concatenate the list of vectors
  Args:
      list: the list of vectors
  
  Returns: the concatenated vector
code: def cat(list: List[EV]) -> EV:
      """
      concatenate the list of vectors
      Args:
          list: the list of vectors
  
      Returns: the concatenated vector
      """
      return _Evaluator.cat(list)
  
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 23 for calling the evaluator obj's underlying member method code with example usage: obj.cat(list) and returns: _Evaluator