input: 
  def create_rest_api() -> str:
      """ Create a basic REST API using Python and Flask to list all the countries in the world.
      The API should have a route '/countries' that returns a JSON list of countries when accessed.
      >>> create_rest_api() == """
      import flask
      from flask import Flask, request, 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()
      """
      True
      """
      pass
  
output:     
      return """
  import flask
  from flask import Flask, request, 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()
  """
  