text: from datetime import datetime
  from app import db, login
  from flask_login import UserMixin
  from werkzeug.security import generate_password_hash, check_password_hash
  
  
  class User(UserMixin, db.Model):
      id = db.Column(db.Integer, primary_key=True)
      username = db.Column(db.String(64), index=True, unique=True)
      email = db.Column(db.String(120), index=True, unique=True)
      password_hash = db.Column(db.String(128))
      posts = db.relationship('Post', backref='author', lazy='dynamic')
  
      def __repr__(self):
          return '<User {}>'.format(self.username)
  
      def set_password(self, password):
          self.password_hash = generate_password_hash(password)
  
      def check_password(self, password):
          return check_password_hash(self.password_hash, password)
  
  
  @login.user_loader
  def load_user(id):
      return User.query.get(int(id))
  
  
  class Post(db.Model):
      id = db.Column(db.Integer, primary_key=True)
      body = db.Column(db.String(140))
      timestamp = db.Column(db.DateTime, index=True, default=datetime.utcnow)
      user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
  
      def __repr__(self):
          return '<Post {}>'.format(self.body)
  