class User(Base):
    __tablename__ = 'ph_user'
    id = Column(Integer, Sequence('user_id_seq'), primary_key=True)
    username = Column(String, unique=True)
    password = Column(String)
    created = Column(DateTime(timezone=True), default=datetime.datetime.now)
    last_login = Column(DateTime(timezone=True), default=datetime.datetime.now)

engine = create_engine(db, echo=False)

@event.listens_for(User.metadata, 'after_create')
def receive_after_create(target, connection, **kw):
    print(target)

Base.metadata.create_all(engine)
self.DBSession = sessionmaker(bind=engine)