code: def test_servers_and_externaldocs(app):
      assert app.external_docs is None
      assert app.servers is None
  
      app.external_docs = {
          "description": "Find more info here",
          "url": "https://docs.example.com/",
      }
      app.servers = [
          {
              "url": "http://localhost:5000/",
              "description": "Development server",
          },
          {
              "url": "https://api.example.com/",
              "description": "Production server",
          },
      ]
  
      rv = app.test_client().get("/openapi.json")
      assert rv.status_code == 200
      validate_spec(rv.json)
      assert rv.json["externalDocs"] == {
          "description": "Find more info here",
          "url": "https://docs.example.com/",
      }
      assert rv.json["servers"] == [
          {
              "url": "http://localhost:5000/",
              "description": "Development server",
          },
          {
              "url": "https://api.example.com/",
              "description": "Production server",
          },
      ]
  
imports: import json
  import pytest
  from flask import request
  from openapi_spec_validator import validate_spec
  from .schemas import Bar
  from .schemas import Baz
  from .schemas import Foo
  from apiflask import APIBlueprint
  from apiflask import Schema
  from apiflask.commands import spec_command
  from apiflask.fields import Integer
label_desc: Use image node_id 10 for calling a global function with example usage: test_servers_and_externaldocs(app) without return types