code: def string_perturb(inp: List[str]) -> List[str]:
      return ["a" + elem for elem in inp]
  
imports: import collections
  from typing import List
  import torch
  from captum.robust import AttackComparator, FGSM
  from tests.helpers.basic import assertTensorAlmostEqual, BaseTest
  from tests.helpers.basic_models import BasicModel, BasicModel_MultiLayer
  from torch import Tensor
label_desc: Use image node_id 6 for calling a global function with example usage: string_perturb(inp) and returns: unknown