old_contents: from sqlalchemy import orm
  
  
  # alias common names
  from sqlalchemy import UniqueConstraint
  from sqlalchemy.ext.associationproxy import association_proxy
  from sqlalchemy.ext.declarative import declared_attr
  from sqlalchemy.ext.hybrid import hybrid_method, hybrid_property
  
  from backend.extensions import db
  
  from .base_model import BaseModel
  from .column import Column
  from .events import attach_events, on, slugify
  from .mixins import PrimaryKeyMixin, TimestampMixin
  from .model import Model
  from .relationships import backref, foreign_key, relationship
  from .types import (
      BigInteger,
      Boolean,
      Date,
      DateTime,
      Float,
      ForeignKey,
      Integer,
      Interval,
      Numeric,
      SmallInteger,
      String,
      Text,
      Time,
  )
  
  session = db.session  # type: orm.session.Session
  
new_contents: from sqlalchemy import orm
  
  
  # alias common names
  from sqlalchemy import UniqueConstraint
  from sqlalchemy.ext.associationproxy import association_proxy
  from sqlalchemy.ext.declarative import declared_attr
  from sqlalchemy.ext.hybrid import hybrid_method, hybrid_property
  
  from backend.extensions import db
  
  from .base_model import BaseModel
  from .column import Column
  from .events import attach_events, on, slugify
  from .mixins import PrimaryKeyMixin, TimestampMixin
  from .model import Model
  from .relationships import backref, foreign_key, relationship
  from .types import (
      BigInteger,
      Boolean,
      Date,
      DateTime,
      Enum,
      Float,
      ForeignKey,
      Integer,
      Interval,
      Numeric,
      SmallInteger,
      String,
      Text,
      Time,
  )
  
  session = db.session  # type: orm.session.Session
  
subject: add missing import