text: from fastapi import FastAPI
  from fastapi.openapi.utils import get_openapi
  
  app = FastAPI()
  
  
  @app.get("/items/")
  async def read_items():
      return [{"name": "Foo"}]
  
  
  def custom_openapi():
      if app.openapi_schema:
          return app.openapi_schema
      openapi_schema = get_openapi(
          title="Custom title",
          version="2.5.0",
          description="This is a very custom OpenAPI schema",
          routes=app.routes,
      )
      openapi_schema["info"]["x-logo"] = {
          "url": "https://fastapi.tiangolo.com/img/logo-margin/logo-teal.png"
      }
      app.openapi_schema = openapi_schema
      return app.openapi_schema
  
  
  app.openapi = custom_openapi
  