defaults = {
    'apt': {
        'packages': {
            'build-essential': {},
            'libssl-dev': {},
            'zlib1g-dev': {},
            'libbz2-dev': {},
            'libreadline-dev': {},
            'libsqlite3-dev': {},
            'curl': {},
            'libncurses-dev': {},
            'xz-utils': {},
            'tk-dev': {},
            'libxml2-dev': {},
            'libxmlsec1-dev': {},
            'libffi-dev': {},
            'liblzma-dev': {},
        },
    },
    'pyenv': {
        'versions': set(),
    },
}