decorator that merges classmethod with property

clsproperty.py

class clsproperty(object):
  """A data descriptor that sets and returns values
      normally and prints a message logging their access.
  """

  def __init__(self, fget=None, fset=None, fdel=None, doc=None):
    self.fget = fget
    self.fset = fset
    self.fdel = fdel
    if doc is None and fget is not None:
      doc = fget.__doc__
    self.__doc__ = doc

  def __get__(self, obj, klass=None):
    if obj is None:
      return self
    if self.fget is None:
      raise AttributeError("unreadable attribute")
    if klass is None:
      klass = type(obj)
    return self.fget(klass, obj)

  def __set__(self, obj, value):
      if self.fset is None:
          raise AttributeError("can't set attribute")
      self.fset(obj, value)

  def __delete__(self, obj):
      if self.fdel is None:
          raise AttributeError("can't delete attribute")
      self.fdel(obj)

  def getter(self, fget):
      return type(self)(fget, self.fset, self.fdel, self.__doc__)

  def setter(self, fset):
      return type(self)(self.fget, fset, self.fdel, self.__doc__)

  def deleter(self, fdel):
      return type(self)(self.fget, self.fset, fdel, self.__doc__)

class ComponentBase:

  FOO = 5

  def __init__(self):
    self.BAR = 15
    pass

  @clsproperty
  def hello_world(cls, self):
    return cls.FOO+self.BAR