[Python-3000] A new member for contextlib?

[Zaur Shibzoukhov]

I suggest a context manager for property defining/redefining. There is a
prototype and illustrative example:

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import sys

null = object()
_property = property
class property(_property):
    #
    def __init__(self, *args, **kw):
        _property.__init__(self, *args, **kw)
        self.__enter__ = self.__enter
        self.__exit__ = self.__exit
    #
    @classmethod
    def __enter__(self):
        return null
    #
    @classmethod
    def __exit__(self, type, value, tb):
        if tb is None:
            frame = sys._getframe(1)
            self.__exitHandler(self, frame.f_locals)
    #
    def __enter(self):
        return null
    #
    def __exit(self, type, value, tb):
        if tb is None:
            frame = sys._getframe(1)
            self.__exitHandler(self, frame.f_locals)
    #
    @staticmethod
    def __exitHandler(self, _locals):
        propName = "_"
        PropName = str(id(self))
        for key, value in _locals.items():
            if value is null:
                propName = key
                PropName = key.capitalize()
                break

        if type(self) == type(property):
            getFunc = _locals.pop('get', None)
            setFunc = _locals.pop('set', None)
            delFunc = _locals.pop('delete', None)
            doc = _locals.pop('doc', None)
        else:
            getFunc = _locals.pop('get', None) or self.fget
            setFunc = _locals.pop('set', None) or self.fset
            delFunc = _locals.pop('delete', None) or self.fdel
            doc = _locals.pop('doc', None) or self.__doc__

        if getFunc:
            funcName = "_get"+PropName
            getFunc.__name__ = funcName
            _locals[funcName] = getFunc
        if setFunc:
            funcName = "_set"+PropName
            setFunc.__name__ = funcName
            _locals[funcName] = setFunc
        if delFunc:
            funcName = "_del"+PropName
            delFunc.__name__ = funcName
            _locals[funcName] = delFunc

        prop = property(getFunc, setFunc, delFunc)
        prop.__doc__ = doc
        _locals[propName] = prop

-----------------------------------------------------------------------------------------------------------

def testPropertyMaker():
    class AAA:
        _v = 1
        with property as v:
            doc = "Example of making property with *with* statement"
            def get(self):
                return self._v
            def set(self, v):
                self._v = v

    class BBB(AAA):
        with AAA.v as v:
            doc = "Example of modified property"
            def get(self):
                return [self._v]

    a=AAA()
    a.v = 10
    print(a.v)
    print(AAA.v.__doc__)

    b=BBB()
    b.v = 100
    print(b.v)
    print(BBB.v.__doc__)

This code is also in attachment.

Is it suitable for contextlib.py?
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