def vault_file(env, default):
    """The path to a misc Vault file
    This function will check for the env override on a file
    path, compute a fully qualified OS appropriate path to
    the desired file and return it if it exists. Otherwise
    returns None
    """
    home = os.environ['HOME'] if 'HOME' in os.environ else \
        os.environ['USERPROFILE']
    filename = os.environ.get(env, os.path.join(home, default))
    filename = abspath(filename)
    if os.path.exists(filename):
        return filename

    return None
The path to a misc Vault file
    This function will check for the env override on a file
    path, compute a fully qualified OS appropriate path to
    the desired file and return it if it exists. Otherwise
    returns None