# demo_descriptors.py

def _get(self, obj, obj_type): print('%s:__get__()' % type(self).__name__)
def _set(self, obj, val): print('%s:__set__()' % type(self).__name__)
def _delete(self, obj): print('%s:__delete__()' % type(self).__name__)

class SetGetDataDescriptor:
  __get__ = _get
  __set__ = _set

class DeleteGetDataDescriptor:
  __get__ = _get
  __delete__ = _delete

class SetOnlyDataDescriptor:
  __set__ = _set

class DeleteOnlyDataDescriptor:
  __delete__ = _delete

class NonDataDescriptor:
  __get__ = _get