code: def gen_str_invalid_vectors(nb, dim):
      vectors = [
          [str(gen_unique_str()) for _ in range(dim)] for _ in range(nb)
      ]
      return vectors
  
imports: import copy
  import json
  import os
  import time
  import numpy
  import pandas
  import random
  from faker import Faker
  from sklearn import preprocessing
  from common.common_func import gen_unique_str
  from common.minio_comm import copy_files_to_minio
  from utils.util_log import test_log
label_desc: Use image node_id 4 for calling a global function with example usage: gen_str_invalid_vectors(nb, dim) and returns: vectors