I downloaded the Python 3.5 source code and ran the following:
$ tar -xf Python-3.5.2.tar.xz
$ sudo make install
sudo make install
Ignoring ensurepip failure: pip 8.1.1 requires SSL/TLS
You are most likely not compiling Python with SSL/TLS support. You are probably missing the SSL development libraries. Install the following dependencies, and then re-configure and re-compile Python 3.5.
apt-get install -y make build-essential libssl-dev zlib1g-dev libbz2-dev libsqlite3-dev
yum install zlib-devel bzip2-devel sqlite sqlite-devel openssl-devel