code: def orion_db(db_type):
      """Return a supported database wrapper instance initiated with test opts."""
      if db_type == "ephemeraldb":
          EphemeralDB.instance = None
          orion_db = EphemeralDB()
      elif db_type == "mongodb":
          MongoDB.instance = None
          orion_db = MongoDB(
              username="user", password="pass", name="orion_test"
          )
      elif db_type == "pickleddb":
          PickledDB.instance = None
          orion_db = PickledDB(host="orion_db.pkl")
      else:
          raise ValueError("Invalid database type")
  
      yield orion_db
  
      if db_type == "ephemeraldb":
          pass
      elif db_type == "mongodb":
          orion_db.close_connection()
      elif db_type == "pickleddb":
          pass
  
imports: import os
  from datetime import datetime
  import pytest
  from orion.core.io.database import Database
  from orion.core.io.database.ephemeraldb import EphemeralDB
  from orion.core.io.database.mongodb import MongoDB
  from orion.core.io.database.pickleddb import PickledDB
label_desc: Use image node_id 4 for calling a global function with example usage: orion_db(db_type) without return types