code: def say_hello():
      """Just Say Hello
  
      It will always return a greeting like this:
      ```
      {'message': 'Hello!'}
      ```
      """
      return {"message": "Hello!"}
  
file_path: apiflask/examples/openapi/basic/app.py
imports: from apiflask import APIFlask, Schema, abort
  from apiflask.fields import Integer, String
  from apiflask.validators import Length, OneOf
label_desc: Use image node_id 1 for calling a global function with example usage: say_hello() and returns: dict