def METHOD_NAME(
    client_id: Optional[str], client_secret: Optional[str]
) -> MutableMapping[str, Union[str, int]]:
    """Make Authorization header for spotify token."""
    if client_id is None:
        client_id = ""
    if client_secret is None:
        client_secret = ""
    auth_header = base64.b64encode(f"{client_id}:{client_secret}".encode("ascii"))
    return {"Authorization": f"Basic {auth_header.decode('ascii')}"}