import time
time_prop = property(lambda self: time.time())

class Class(object):
    """
    >>> Class.time
    <property object at ...>
    >>> instance = Class()
    >>> instance.time == instance.time
    False
    """
    time = time_prop

def class_decorator(C):
    """
    >>> class Class(object):
    ...     "will magically tells the time"
    >>> Class = class_decorator(Class)
    >>> Class().time == Class().time
    False
    """
    return type(C.__name__,
                C.__bases__,
                dict(C.__dict__, time=time_prop))

class TimedType(type):
    """
    >>> TimedClass = TimedType('TimedClass', (object,), {'x': 1})
    >>> TimedClass.__class__
    <class '__main__.TimedType'>
    >>> TimedType.time
    <property object at ...>
    >>> TimedClass.time == TimedClass.time
    False
    >>> TimedClass().time
    Traceback (most recent call last):
        ...
    AttributeError: 'TimedClass' object has no attribute 'time'
    """
    time = time_prop

TimedClass = TimedType('TimedClass', (object,), {'x': 1})

class Enum(int):
    class __metaclass__(type):
        def __new__(metaclass, name, bases, members):
            Class = type.__new__(metaclass, name, bases, members)
            Class._names = {}
            for k, v in members.items():
                if isinstance(v, (int, long)):
                    setattr(Class, k, Class(v))
                    Class._names[v] = k
            return Class

    def __str__(self):
        return '%s.%s' % (self.__class__.__name__,
                          self._names.get(self, int(self)))

class FooBar(Enum):
    """
    >>> print FooBar(0), FooBar.BAR
    FooBar.FOO FooBar.BAR
    """
    FOO = 0
    BAR = 1

import UserDict

class Dict(object):
    class __metaclass__(type):  # , UserDict.DictMixin
        __getitem__ = type.__getattribute__
        __setitem__ = type.__setattr__

class A(Dict):
    foo = 1

class B(A):
    """
    >>> B['bar']
    2
    >>> B['foo']
    1
    >>> A['foo'] = 0
    >>> B['foo']
    0
    """
    bar = 2

# Test
if __name__ == '__main__':
    import doctest
    doctest.testmod(optionflags=doctest.ELLIPSIS)