code: def override_serve_dashboard():
      uid = "test_serve_uid_ses_12345"
      global_filters = 'TestVar="$TestVariableValue"'
  
      os.environ["RAY_GRAFANA_SERVE_DASHBOARD_UID"] = uid
      os.environ[
          "RAY_GRAFANA_SERVE_DASHBOARD_GLOBAL_FILTERS"
      ] = global_filters
      yield uid, global_filters
      del os.environ["RAY_GRAFANA_SERVE_DASHBOARD_GLOBAL_FILTERS"]
      del os.environ["RAY_GRAFANA_SERVE_DASHBOARD_UID"]
  
file_path: ray/python/ray/tests/test_metrics_head.py
imports: import json
  import logging
  import os
  import pytest
  import sys
  import tempfile
  from ray.dashboard.modules.metrics.dashboards.default_dashboard_panels import DEFAULT_GRAFANA_PANELS
  from ray.dashboard.modules.metrics.dashboards.serve_dashboard_panels import SERVE_GRAFANA_PANELS
  from ray.tests.conftest import _ray_start
label_desc: Use image node_id 4 for calling a global function with example usage: override_serve_dashboard() without return types