code: def test_ray_start_set_node_labels_value_error():
      out = check_cmd_stderr(["ray", "start", "--head", "--labels=xxx"])
      assert "is not a valid JSON string, detail error" in out
  
      out = check_cmd_stderr(
          ["ray", "start", "--head", '--labels={"gpu_type":1}']
      )
      assert 'The value of the "gpu_type" is not string type' in out
  
      out = check_cmd_stderr(
          [
              "ray",
              "start",
              "--head",
              '--labels={"ray.io/node_id":"111"}',
          ]
      )
      assert "cannot start with the prefix `ray.io/`" in out
  
      out = check_cmd_stderr(
          [
              "ray",
              "start",
              "--head",
              '--labels={"ray.io/other_key":"111"}',
          ]
      )
      assert "cannot start with the prefix `ray.io/`" in out
  
file_path: ray/python/ray/tests/test_node_labels.py
imports: import os
  import sys
  import pytest
  import subprocess
  import ray
  from ray.cluster_utils import AutoscalingCluster
  from ray._private.test_utils import wait_for_condition
label_desc: Use image node_id 7 for calling a global function with example usage: test_ray_start_set_node_labels_value_error() without return types