Best way to access table instances when using SQLAlchemy's declarative syntax

class Users(Base):
    __tablename__   = 'users'
    __table_args__  = {'autoload':True}

users = Users()
print users.__table__.select()

users.select()

session.query(User)

conn.execute(users.update(users.c.name=='jack'), name='ed')

Base.metadata.tables["users"]