tallero [1] filed an orphan request for python2-decorator [2]: I have published an upgrade here: https://github.com/themartiancompany/python2-decorator-ur . The package is neededto build python2-traitlets which is needed to build ipython2.
[1] https://aur.archlinux.org/account/tallero/ [2] https://aur.archlinux.org/pkgbase/python2-decorator/
