input: from typing import List, Dict
  
  def list_all_countries() -> Dict[str, List[str]]:
      """
      Create a basic REST API using Python and Flask to list all the countries in the world.
      The function reads a JSON file containing a list of countries and returns it as a JSON response.
      
      >>> list_all_countries()
      {'countries': ['Afghanistan', 'Albania', 'Algeria', 'Andorra', 'Angola', 'Antigua and Barbuda', 'Argentina', 'Armenia', 'Australia', 'Austria', 'Azerbaijan']}
      """
output:     import json
      from flask import Flask, jsonify
  
      app = Flask(__name__)
  
      @app.route('/countries', methods=['GET'])
      def get_countries():
          with open('countries.json', 'r') as file:
              countries = json.load(file)
          return jsonify({'countries': countries})
  
      if __name__ == '__main__':
          app.run(debug=True)