class_docstr: Decorator that marks that an attribute of a class should not be
  computed until needed, and that the value should be memoized.
  
  Example
  -------
  
  >>> from catalyst.utils.memoize import classlazyval
  >>> class C(object):
  ...     count = 0
  ...     @classlazyval
  ...     def val(cls):
  ...         cls.count += 1
  ...         return "val"
  ...
  >>> C.count
  0
  >>> C.val, C.count
  ('val', 1)
  >>> C.val, C.count
  ('val', 1)
code: def __get__(self, instance, owner):
      return super(classlazyval, self).__get__(owner, owner)
  
imports: from collections import OrderedDict, Sequence
  from functools import wraps
  from itertools import compress
  from weakref import WeakKeyDictionary, ref
  from six.moves._thread import allocate_lock
  from toolz.sandbox import unzip
label_desc: Use image node_id 1 for calling the classlazyval obj's underlying member method code with example usage: obj.__get__(instance, owner) and returns: super