text: import sqlite3
  from db import db
  
  
  class UserModel(db.Model):
  
      __tablename__ = 'users'
  
      id = db.Column(db.Integer, primary_key=True)
      username = db.Column(db.String(50))
      password = db.Column(db.String(50))
  
      def __init__(self, username, password):
          self.username = username
          self.password = password
     
      def save_to_db(self):
          db.session.add(self)
          db.session.commit()
  
      def delete_from_db(self):
          db.session.delete(self)
          db.session.commit()
  
      @classmethod
      def find_by_username(cls, username):
          return cls.query.filter_by(username=username).first()
          
      @classmethod
      def find_by_id(cls, _id):
          return cls.query.filter_by(id=_id).first()
          