input: Write a function named `create_country_api` that creates a basic REST API using Flask to list all the countries in the world. The API should have a route named `/countries` that, when accessed via HTTP GET, reads the list of countries from a JSON file named `data.json` and returns it in JSON format. The function should return the Flask app object. If the JSON file is empty or does not contain a list of countries, the function should handle it gracefully and return an empty list.
  assert create_country_api().test_client().get('/countries').status_code == 200
  assert create_country_api().test_client().get('/countries').get_json() == {"countries": ["USA", "Canada", "Mexico"]}
  assert create_country_api().test_client().get('/countries').get_json() == {"countries": []}
output: from flask import Flask, jsonify
  import json
  
  def create_country_api():
      app = Flask(__name__)
      
      @app.route('/countries', methods=['GET'])
      def get_countries():
          try:
              with open('data.json', 'r') as file:
                  data = json.load(file)
                  countries = data.get('countries', [])
          except (FileNotFoundError, json.JSONDecodeError):
              countries = []
          
          return jsonify({'countries': countries})
      
      return app