code: def connection(self, host, port, user, password, db_name, milvus_ns):
      if user and password:
          log.info(
              f"connect to {host}:{port} with user {user} and password {password}"
          )
          connections.connect(
              "default",
              uri=f"{host}:{port}",
              token=f"{user}:{password}",
          )
      else:
          connections.connect("default", host=host, port=port)
      if connections.has_connection("default") is False:
          raise Exception("no connections")
      all_dbs = db.list_database()
      log.info(f"all dbs: {all_dbs}")
      if db_name not in all_dbs:
          db.create_database(db_name)
      db.using_database(db_name)
      log.info(
          f"connect to milvus {host}:{port}, db {db_name} successfully"
      )
      self.host = host
      self.port = port
      self.user = user
      self.password = password
      self.milvus_ns = milvus_ns
  
file_path: milvus/tests/python_client/chaos/testcases/test_concurrent_operation_for_multi_tenancy.py
imports: import time
  import pytest
  import threading
  import json
  from time import sleep
  from pymilvus import connections, db
  from chaos.checker import InsertChecker, UpsertChecker, SearchChecker, QueryChecker, DeleteChecker, Op, ResultAnalyzer
  from utils.util_log import test_log
  from chaos import chaos_commons
  from common.common_type import CaseLabel
  from chaos import constants
label_desc: Use image node_id 1 for calling the TestOperations obj's underlying member method code with example usage: obj.connection(host, port, user, password, db_name, milvus_ns) without return types