Partially Persistent Data

field.py

class Field:
  def __get__(self, obj, obj_type=None):
    if not obj:
      return self
    
    return getattr(obj.view(), self.__name__)
  
  def __set__(self, obj, value):
    obj.update(self.__name__=value)
  
  def __set_name__(self, name):
    self.__name__ = name