Return the path to the site-packages directory of a virtualenv

    venv
        Path to the virtualenv.

    CLI Example:

    .. code-block:: bash

        salt '*' virtualenv.get_site_packages /path/to/my/venv

def get_site_packages(venv):
    '''
    Return the path to the site-packages directory of a virtualenv

    venv
        Path to the virtualenv.

    CLI Example:

    .. code-block:: bash

        salt '*' virtualenv.get_site_packages /path/to/my/venv
    '''
    bin_path = _verify_virtualenv(venv)

    ret = __salt__['cmd.exec_code_all'](
        bin_path,
        'from distutils import sysconfig; '
            'print(sysconfig.get_python_lib())'
    )

    if ret['retcode'] != 0:
        raise CommandExecutionError('{stdout}\n{stderr}'.format(**ret))

    return ret['stdout']