input: from typing import Tuple
  
  def create_rest_api() -> Tuple[Flask, str]:
      """ Creates a basic REST API using Python and Flask to list all the countries in the world.
      The API should read the list of countries from a JSON file named 'data.json' and return the data when accessed at the route '/countries'.
      >>> app, route = create_rest_api()
      >>> app.test_client().get(route).json['countries'][0]
      'Afghanistan'
      """
      import flask
      from flask import Flask, jsonify
      import json
  
      app = Flask(__name__)
  
      @app.route('/countries', methods=['GET'])
      def get_countries():
          with open('data.json', 'r') as f:
              countries = json.load(f)
          return jsonify(countries)
  
      if __name__ == '__main__':
          app.run()
      
      return app, '/countries'
output:     
      import flask
      from flask import Flask, jsonify
      import json
  
      app = Flask(__name__)
  
      @app.route('/countries', methods=['GET'])
      def get_countries():
          with open('data.json', 'r') as f:
              countries = json.load(f)
          return jsonify(countries)
  
      if __name__ == '__main__':
          app.run()
      
      return app, '/countries'
  