old_contents: from connexion.resolver import RestyResolver
  from flask import current_app, request, abort, jsonify, g, url_for
  from flask_httpauth import HTTPAuth
  
  __all__ = ["login", "register", "add_bucket_list", "get_bucket_lists",
             "get_bucket_list","put_bucket_list","delete_bucket_list",
             "create_item_in_bucket_list", "get_items_in_bucket_list",
             "update_bucket_list_item", "delete_bucket_list_item"]
  
  
  def login():
      pass
  
  
  def register():
      pass
  
  
  def add_bucket_list():
      pass
  
  
  def get_bucket_lists():
      pass
  
  
  def get_bucket_list():
      pass
  
  
  def put_bucket_list():
      pass
  
  
  def delete_bucket_list():
      pass
  
  
  def create_item_in_bucket_list():
      pass
  
  
  def get_items_in_bucket_list():
      pass
  
  
  def update_bucket_list_item():
      pass
  
  
  def delete_bucket_list_item():
      pass
  
  from api.models import User, BucketList, Item
  
new_contents: from connexion.resolver import RestyResolver
  from flask import request, abort, jsonify, g, url_for
  from flask_httpauth import HTTPAuth
  import re
  
  __all__ = ["login", "register", "add_bucket_list", "get_bucket_lists",
             "get_bucket_list","put_bucket_list","delete_bucket_list",
             "create_item_in_bucket_list", "get_items_in_bucket_list",
             "update_bucket_list_item", "delete_bucket_list_item"]
  
  EMAIL_REGEX = re.compile(r"[^@]+@[^@]+\.[^@]+")
  
  
  def login(username, password):
      pass
  
  
  def register():
      data = request.get_json()
      first_name = data['first_name']
      last_name = data['last_name']
      email = data['email']
      username = data['username']
      password = data['password']
  
      user = User(first_name, last_name, email, username)
      user.hash_password(password)
  
      if not first_name.isalpha():
          response = jsonify({'message': 'First name must be string alphabet type'})
          response.status_code = 400
          return response
  
      if not last_name.isalpha():
          response = jsonify({'message': 'Last name must be string alphabet type'})
          response.status_code = 400
          return response
  
      if not username or not password:
          response = jsonify({'error': 'Username or password should not be left blank'})
          response.status_code = 400
          return response
  
      if not EMAIL_REGEX.match(email):
          response = jsonify({'message': 'Please specify valid email address'})
          return response
  
      if len(password) < 6:
          response = jsonify({'error': 'Password is too short, it must be more than 6 characters'})
          response.status_code = 401
          return response
  
      user.hash_password(data['password'])
      db.session.add(user)
      db.session.commit()
      return jsonify({'message': 'User has been successfully created'})
  
  
  def add_bucket_list():
      pass
  
  
  def get_bucket_lists():
      pass
  
  
  def get_bucket_list(id):
      pass
  
  
  def put_bucket_list():
      pass
  
  
  def delete_bucket_list():
      pass
  
  
  def create_item_in_bucket_list():
      pass
  
  
  def get_items_in_bucket_list():
      pass
  
  
  def update_bucket_list_item():
      pass
  
  
  def delete_bucket_list_item():
      pass
  
  from api.models import User, BucketList, Item
  from api  import db
  
subject: Implement register user api method