def METHOD_NAME(upstream: str, downstream: str, version: str, author: str):
    """
    Merge the upstream specfile with the changelog from downstream and add a new
    changelog entry.
    """
    upstream_spec_lines = upstream.splitlines()
    downstream_spec_lines = downstream.splitlines()
    # Find where changelog starts in both specfiles
    changelog_start_in_up_spec = upstream_spec_lines.index("%changelog")
    changelog_start_in_down_spec = downstream_spec_lines.index("%changelog")
    # Create a new changelog entry
    date = datetime.now().strftime("%a %b %d %Y")
    changelog = f"""\