code: def exists_collection(self, collection_name=None):
      if collection_name is None:
          collection_name = self._collection_name
      res = self._milvus.has_collection(collection_name)
      return res
  
imports: import random
  import logging
  import time
  from multiprocessing import Process
  from pymilvus import Milvus, DataType
  import utils
  import config
  from milvus_benchmark.runners import utils
label_desc: Use image node_id 32 for calling the MilvusClient obj's underlying member method code with example usage: obj.exists_collection(collection_name) and returns: res