input: Write a function that demonstrates how to create a REST API using Flask in Python to delete an item from a list. The function should include the necessary routes and methods for both retrieving the list of items and deleting a specific item.
  
  from flask import Flask, request
  import json
  
  app = Flask(__name__)
  items = ["Apple", "Banana", "Orange"]
  
  @app.route('/items', methods=["GET"])
  def get_items():
   return json.dumps(items)
  
  @app.route('/items/<item>', methods=["DELETE"])
  def delete_item(item):
   if item in items:
    items.remove(item)
    message = "Item successfully deleted."
   else:
    message = "Item not found."
   return json.dumps({"message": message})
  
  assert get_items() == '["Apple", "Banana", "Orange"]'
  assert delete_item("Banana") == '{"message": "Item successfully deleted."}'
  assert get_items() == '["Apple", "Orange"]'
  assert delete_item("Grape") == '{"message": "Item not found."}'
output: 
  @app.route('/items', methods=["GET"])
  def get_items():
   return json.dumps(items)
  
  @app.route('/items/<item>', methods=["DELETE"])
  def delete_item(item):
   if item in items:
    items.remove(item)
    message = "Item successfully deleted."
   else:
    message = "Item not found."
   return json.dumps({"message": message})
  