I have compiled Python3.7 latest source (at time of writing) via
tazpkg install libffi-devel zlib-dev linux-api-headers gcc make
wget https://www.python.org/ftp/python/3.7.0/Python-3.7.0.tgz
tar -xf Python-3.7.0.tgz
cd Python-3.7.0
./configure --enable-optimizations
make
sudo make install
Please add this to the repo, since python 3.4 (py3k package) is pretty old and many improvements were made in 3.5 and 3.6 that are sorely missed