pyenv is a Simple Python version management.

I use it on CentOS 6 because upgrade system's python 2.6 would broke many things.

git clone https://github.com/yyuu/pyenv.git ~/.pyenv
echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bashrc
echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(pyenv init -)"' >> ~/.bashrc

Install Python 2.7:

pyenv install 2.7.12

Use pyenv's python on specify directory:

cd /path/to/project && pyenv init .
python --version   # 2.7.12