if key id deprecated and a replacement key defined, will return the
    replacement key, otherwise returns `key` as - is

def _translate_key(key):
    """
    if key id deprecated and a replacement key defined, will return the
    replacement key, otherwise returns `key` as - is
    """

    d = _get_deprecated_option(key)
    if d:
        return d.rkey or key
    else:
        return key