code: def get_random_string(length):
      # choose from all lowercase letter
      letters = string.ascii_lowercase
      result_str = "".join(
          [random.choice(letters) for i in range(length)]
      )
      return result_str
  
imports: import copy
  import json
  import os
  import random
  import re
  import signal
  import string
  from collections import defaultdict
  from subprocess import Popen
  from subprocess import STDOUT
  import google.protobuf.json_format
  import google.protobuf.text_format
  import psutil
  import requests
  from .proto.model_config_pb2 import ModelConfig
  from visualdl.utils.dir import FASTDEPLOYSERVER_PATH
label_desc: Use image node_id 13 for calling a global function with example usage: get_random_string(length) and returns: result_str