code: def clear_uri():
      mlflow.gateway.utils._gateway_uri = None
  
imports: from unittest import mock
  import pytest
  from requests.exceptions import HTTPError, Timeout
  import mlflow.gateway.utils
  from mlflow.environment_variables import MLFLOW_GATEWAY_URI
  from mlflow.exceptions import InvalidUrlException, MlflowException
  from mlflow.gateway import MlflowGatewayClient, set_gateway_uri
  from mlflow.gateway.config import Route
  from mlflow.gateway.constants import MLFLOW_GATEWAY_SEARCH_ROUTES_PAGE_SIZE
  from mlflow.gateway.utils import resolve_route_url
  from tests.gateway.tools import Gateway, save_yaml
label_desc: Use image node_id 4 for calling a global function with example usage: clear_uri() without return types