gistfile1.py

  class Entity:
    def __init__(self, jsonData)
      self.jsonData = jsonData

    @classmethod
    def register_fields(cls, *fields):
      for name in fields:
        setattr(cls, name, property(lambda cls: cls.jsonData[name]))
 
  class Org(Entity):
    pass

  Org.register_fields("avatar_url", "billing_email")