simple_entity_metaclass.py

class EntityMeta(type):
  """Metaclass for business entities with validated fields"""
  
  def __init__(cls, name, bases, attr_dict):
    # handover to type.__init__
    super().__init__(name, bases, attr_dict)
    for key, attr in attr_dict.items():
        if isinstance(attr, Validated):
          type_name = type(attr).__name__
          attr.storage_name = f'_{type_name}#{key}'
  
  class Entity(metaclass=EntityMeta):
     """Shortcut class for direct inheritance."""