input: from typing import List
  
  def list_countries_api() -> None:
      """Creates a basic REST API using Python and Flask to list all the countries in the world.
      The API will return a JSON response containing all the countries loaded from a 'data.json' file.
      >>> list_countries_api()
      Running the Flask app at `http://127.0.0.1:5000/countries` should return a JSON list of all countries.
      """
output:     
      from flask import Flask, jsonify
      import json
  
      app = Flask(__name__)
  
      @app.route('/countries', methods=['GET'])
      def get_countries():
          with open('data.json', 'r') as file:
              countries = json.load(file)
          return jsonify(countries)
  
      if __name__ == '__main__':
          app.run(debug=True)
  