import pypandoc

middle = pypandoc.convert_file("body.md", "html")

with open("top.html", "r") as top:
    with open("bottom.html", "r") as bottom:
        with open("index.html", "w") as index:
            index.write(top.read())
            index.write(middle)
            index.write(bottom.read())
            index.close()