code: def t_drop_ml_engine(self, client_con, mock_executor):
      client_con.myproj.ml_engines.delete_one({"name": "openai2"})
  
      ast = mock_executor.call_args[0][0]
  
      expected_sql = "DROP ML_ENGINE openai2"
      assert (
          parse_sql(expected_sql, "mindsdb").to_string()
          == ast.to_string()
      )
  
imports: import datetime
  import json
  import threading
  import inspect
  from unittest.mock import patch
  import tempfile
  import os
  from pymongo import MongoClient
  from mindsdb_sql import parse_sql
  from mindsdb.api.executor.data_types.answer import ExecuteAnswer, ANSWER_TYPE
  from mindsdb.api.executor import Column
  from .executor_test_base import BaseUnitTest
label_desc: Use image node_id 11 for calling the TestMongoDBServer obj's underlying member method code with example usage: obj.t_drop_ml_engine(client_con, mock_executor) without return types