input: Write a function to create a REST API in Python that can be used to delete an item from a list and return a message indicating whether the deletion was successful or if the item was not found. The API should include a GET route to retrieve the list of items and a DELETE route to remove a specific item.
  assert create_rest_api().get('/items').data == b'["Apple", "Banana", "Orange"]'
  assert create_rest_api().delete('/items/Banana').data == b'{"message": "Item successfully deleted."}'
  assert create_rest_api().get('/items').data == b'["Apple", "Orange"]'
  assert create_rest_api().delete('/items/Grape').data == b'{"message": "Item not found."}'
  assert create_rest_api().get('/items').data == b'["Apple", "Orange"]'
output: 
  from flask import Flask, jsonify, abort
  
  def create_rest_api():
      app = Flask(__name__)
      items = ["Apple", "Banana", "Orange"]
  
      @app.route('/items', methods=['GET'])
      def get_items():
          return jsonify(items)
  
      @app.route('/items/<string:item>', methods=['DELETE'])
      def delete_item(item):
          if item in items:
              items.remove(item)
              return jsonify({"message": "Item successfully deleted."})
          else:
              return jsonify({"message": "Item not found."})
  
      return app
  