Use PyString_AsStringAndSize to avoid strlen
Use PyString_AsStringAndSize to avoid strlen

This should make the operation microscopically faster.

A second difference is that strings with embedded NULLs will now be
allowed, although I'm not really sure what is the impact of that
change.

again4you/python-systemd,again4you/python-systemd,Awesense/python-systemd,davidstrauss/python-systemd,Awesense/python-systemd,davidstrauss/python-systemd,Awesense/python-systemd,keszybz/python-systemd,systemd/python-systemd,glittershark/python-systemd,keszybz/python-systemd,systemd/python-systemd,glittershark/python-systemd