code: def get_storage_url(specifier: str) -> Iterator:
      tmpfile = None
      try:
          if specifier == "inmemory":
              url = None
          elif specifier == "sqlite":
              tmpfile = NamedTemporaryFilePool().tempfile()
              url = "sqlite:///{}".format(tmpfile.name)
          else:
              raise ValueError(
                  "Invalid specifier entered. Was expecting 'inmemory' or 'sqlite'"
                  f"but got {specifier} instead"
              )
          yield url
      finally:
          if tmpfile is not None:
              tmpfile.close()
  
imports: from contextlib import contextmanager
  import time
  from typing import Iterator
  import numpy
  import pytest
  import optuna
  from optuna._imports import try_import
  from optuna.integration.dask import _OptunaSchedulerExtension
  from optuna.integration.dask import DaskStorage
  from optuna.testing.tempfile_pool import NamedTemporaryFilePool
  from optuna.trial import Trial
label_desc: Use image node_id 1 for calling a global function with example usage: get_storage_url(specifier) without return types