code: def clean_mongodb():
      """Clean collections."""
      client = MongoClient(
          username="user", password="pass", authSource="orion_test"
      )
      database = client.orion_test
      database.experiments.drop()
      database.lying_trials.drop()
      database.trials.drop()
      database.workers.drop()
      database.resources.drop()
      client.close()
  
imports: import os
  import shutil
  import subprocess
  import pytest
  from pymongo import MongoClient
  import orion.core.cli
  import orion.core.io.experiment_builder
  from orion.client import create_experiment
  from orion.core.io.database import database_factory
  from orion.storage.base import storage_factory
label_desc: Use image node_id 5 for calling a global function with example usage: clean_mongodb() without return types