docstr: slice a[start:start+size]
  Args:
      a: the vector to slice
      start: the start index
      size: the size to slice
  
  Returns:
      the sliced vector
code: def slice(a: EV, start: int, size: int) -> EV:
      """
      slice a[start:start+size]
      Args:
          a: the vector to slice
          start: the start index
          size: the size to slice
  
      Returns:
          the sliced vector
      """
      return a.slice(start, size)
  
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 17 for calling the evaluator obj's underlying member method code with example usage: obj.slice(a, start, size) and returns: a