old_contents: from sqlalchemy.ext.declarative import declared_attr
  from sqlalchemy import Table, Column, Integer, String, MetaData, ForeignKey, DateTime
  import sqlalchemy.types as types
  from sqlalchemy.types import String
  from flask import g
  import uuid
  import datetime
  
  try:
      from app import db
  except ImportError:
      raise Exception('db not found please use required skeleton application see documentation')
  
  
  class FileColumn(types.TypeDecorator):
      """
      Extends SQLA to support a File Column
      usefull to auto form generation.
      
      """
      impl = types.Text
      
  
  class ImageColumn(types.TypeDecorator):
      impl = types.Text
  
  
  
  class BaseMixin(object):
      __table_args__ = {'extend_existing': True}
  
  
  class AuditMixin(BaseMixin):
      """
      AuditMixin
      Mixin for models, add 4 cols to stamp, time and user on
      creation and modification
      """
      created_on = db.Column(db.DateTime, default=datetime.datetime.now,nullable=False)
      changed_on = db.Column(db.DateTime, default=datetime.datetime.now,
                              onupdate=datetime.datetime.now,nullable=False)
  
      @declared_attr
      def created_by_fk(cls):
          return db.Column(db.Integer, db.ForeignKey('user.id'),
                  default=cls.get_user_id,nullable=False)
  
      @declared_attr
      def created_by(cls):
          return db.relationship("User", primaryjoin='%s.created_by_fk == User.id'%cls.__name__)
  
      @declared_attr
      def changed_by_fk(cls):
          return db.Column(db.Integer, db.ForeignKey('user.id'),
                  default=cls.get_user_id,onupdate=cls.get_user_id,nullable=False)
  
      @declared_attr
      def changed_by(cls):
          return db.relationship("User", primaryjoin='%s.changed_by_fk == User.id'%cls.__name__)
  
  
      @classmethod
      def get_user_id(cls):
          return g.user.id
  
new_contents: from sqlalchemy.ext.declarative import declared_attr
  from sqlalchemy import Table, Column, Integer, String, MetaData, ForeignKey, DateTime
  import sqlalchemy.types as types
  from sqlalchemy.types import String
  from flask import g
  import uuid
  import datetime
  
  #try:
  #    from app import db
  #except ImportError:
  #    raise Exception('db not found please use required skeleton application see documentation')
  
  
  class FileColumn(types.TypeDecorator):
      """
      Extends SQLA to support a File Column
      usefull to auto form generation.
      
      """
      impl = types.Text
      
  
  class ImageColumn(types.TypeDecorator):
      impl = types.Text
  
  
  
  class BaseMixin(object):
      __table_args__ = {'extend_existing': True}
  
  
  class AuditMixin(BaseMixin):
      """
      AuditMixin
      Mixin for models, add 4 cols to stamp, time and user on
      creation and modification
      """
      created_on = Column(DateTime, default=datetime.datetime.now,nullable=False)
      changed_on = Column(DateTime, default=datetime.datetime.now,
                              onupdate=datetime.datetime.now,nullable=False)
  
      @declared_attr
      def created_by_fk(cls):
          return Column(Integer, ForeignKey('user.id'),
                  default=cls.get_user_id,nullable=False)
  
      @declared_attr
      def created_by(cls):
          return relationship("User", primaryjoin='%s.created_by_fk == User.id'%cls.__name__)
  
      @declared_attr
      def changed_by_fk(cls):
          return Column(Integer, ForeignKey('user.id'),
                  default=cls.get_user_id,onupdate=cls.get_user_id,nullable=False)
  
      @declared_attr
      def changed_by(cls):
          return relationship("User", primaryjoin='%s.changed_by_fk == User.id'%cls.__name__)
  
  
      @classmethod
      def get_user_id(cls):
          return g.user.id
  
subject: Update mixins.py