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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _get_storage_api(retry_params, account_id=None):
 """Returns storage_api instance for API methods. Args: retry_params: An instance of api_utils.RetryParams. If none, thread's default will be used. account_id: Internal-use only. Returns: A storage_api instance to handle urlfetch work to GCS. On dev appserver, this instance will talk to a local stub by default. However, if you pass the arguments --appidentity_email_address and --appidentity_private_key_path to dev_appserver.py it will attempt to use the real GCS with these credentials. Alternatively, you can set a specific access token with common.set_access_token. You can also pass --default_gcs_bucket_name to set the default bucket. """



  api = _StorageApi(_StorageApi.full_control_scope,
                    service_account_id=account_id,
                    retry_params=retry_params)

  # when running local unit tests, the service account is test@localhost
  # from google.appengine.api.app_identity.app_identity_stub.APP_SERVICE_ACCOUNT_NAME
  service_account = app_identity.get_service_account_name()
  if (common.local_run() and not common.get_access_token()
      and (not service_account or service_account.endswith('@localhost'))):
    api.api_url = common.local_api_url()
  if common.get_access_token():
    api.token = common.get_access_token()
  return api