def set_properties(names_to_docs):
    def decorator(cls):
        for name, doc in names_to_docs.items():
            prop = property((lambda self: getattr(self, '_{}'.format(name))),
                            (lambda self, val: setattr(self, '_{}'.format(name), val),
                            doc=doc)
            setattr(cls, name, prop)
        return cls
    return decorator

>>> @set_properties({'a': 'This is a', 'b': 'This is b'})
>>> class Test:
...     def __init__(self):
...         self._a = 1
...         self._b = 2
...
>>> print(Test.a.__doc__)
This is a
>>> Test().a
1