code: def get_file_url(self, key, method="GET"):
      assert method == "GET"
      self.logger.debug(
          "Getting a download url for a file at key {}".format(key)
      )
  
      response_dict, url = self._get_file_meta(key)
      if response_dict is None:
          self.logger.debug("Getting file metainfo failed")
          return None
  
      self.logger.debug("Done")
      return url + "?alt=media&token=" + response_dict["downloadTokens"]
  
imports: import time
  import calendar
  import certifi
  import json
  from studio import pyrebase
  from studio.util import logs
  from studio.auth import get_auth
  from studio.storage.storage_setup import get_storage_verbose_level
  from studio.storage.storage_type import StorageType
  from studio.storage.storage_handler import StorageHandler
label_desc: Use image node_id 5 for calling the FirebaseStorageHandler obj's underlying member method code with example usage: obj.get_file_url(key, method) and returns: unknown, None