The documentation uses the function signature 
`abc.abstractproperty(fget[, fset[, fdel[, doc]]])`, implying that 
fget is mandatory, and all other arguments are optional. The correct 
version would be `abc.abstractproperty([fget[, fset[, fdel[, 
doc]]]])`, or else to change abc.abstractproperty() to require fget (I 
have not compiled 2.7+ to test if this is the case, I only know that 
the docs in trunk continue to use this signature).

I initially suspected that I misunderstood the signature syntax, but 
other functions use it as I would assume-- for instance, the Built-In 
Functions documentation lists `property([fget[, fset[, fdel[, 
doc]]]])`.

Fixed in r70828, thanks!