input: Write a Python function to create a Flask API with a resource that supports GET, POST, and DELETE methods.
  assert create_flask_api().post('/post/1', json={'title': 'Title 1', 'content': 'Content 1'}).status_code == 201
  assert create_flask_api().get('/post/1').status_code == 404
  assert create_flask_api().delete('/post/1').status_code == 200
output: def create_flask_api():
      from flask import Flask, jsonify, request, abort
      
      app = Flask(__name__)
      posts = {}
      
      @app.route('/post/<int:post_id>', methods=['GET'])
      def get_post(post_id):
          post = posts.get(post_id)
          if post is None:
              abort(404)
          return jsonify(post)
      
      @app.route('/post/<int:post_id>', methods=['POST'])
      def create_post(post_id):
          if post_id in posts:
              abort(400)
          post_data = request.get_json()
          posts[post_id] = post_data
          return jsonify({'message': 'Post created'}), 201
      
      @app.route('/post/<int:post_id>', methods=['DELETE'])
      def delete_post(post_id):
          if post_id not in posts:
              abort(404)
          del posts[post_id]
          return jsonify({'message': 'Post deleted'}), 200
      
      return app