Hello,
I was recently porting my application from Py2 to Py3 and encountered error, when I accidentally became unable to define my own pickling mechanism for functions.
Before that I was using it to pickle pure lambdas, registering my own handler for cPickle with copy_reg, but after [1] (and release 3.4) it seems that feature has been removed.
As it mentioned in commit message, this was done for compatibility with pure-python pickle. So I have to ask, may be it would be better to revert the commit and add the corresponding feature to pure-python pickle implementation?