pyenv(){
    if [ $# -gt 0 ]; then
        ver=$1
    else
        ver='2.7'
    fi

    case $ver in
        '2.6')
            name="2-6"
            container='terzom/python'
            ;;
        *)
            name=$(echo $ver|awk '{sub(/\./, "-"); print}')
            container="python:$ver"
            ;;
    esac
    docker run --hostname py$name -it -v ${PWD}:/src -w /src \
        ${container} /bin/bash
}