text: # coding=utf-8
  
  from datetime import datetime
  from sqlalchemy import create_engine, Column, String, Integer, DateTime
  from sqlalchemy.ext.declarative import declarative_base
  from sqlalchemy.orm import sessionmaker
  
  db_url = 'localhost:5432'
  db_name = 'online-exam'
  db_user = 'postgres'
  db_password = 'ONLIN3-ex4m'
  engine = create_engine(f'postgresql://{db_user}:{db_password}@{db_url}/{db_name}')
  Session = sessionmaker(bind=engine)
  
  Base = declarative_base()
  
  class Entity():
      id = Column(Integer, primary_key=True)
      create_at = Column(DateTime)
      updated_at = Column(DateTime)
      last_updated_by = Column(String)
  
      def __init__(self, created_by):
          self.create_at = datetime.now()
          self.updated_at = datetime.now()
          self.last_updated_by =  created_by