human
I wrote the below code

    pack = unpack = None
    try:
        import msgpack
        if (msgpack.version >= (0, 4)):
            from msgpack import packb, unpackb
            def pack(s):
                return packb(s, use_bin_type=True)
            def unpack(s):
                return unpackb(s, encoding=u'utf-8')
        else:
            def version_mismatch(*args, **kwargs):
                raise SerializerNotInstalled(u'msgpack    requires    msgpack-python    >=    0.4.0')
            pack = unpack = version_mismatch
    except (ImportError, ValueError):
        def not_available(*args, **kwargs):
            raise SerializerNotInstalled(u'No    decoder    installed    for    msgpack.    Please    install    the    msgpack-python    library')
        pack = unpack = not_available
    registry.register(u'msgpack', pack, unpack, content_type=u'application/x-msgpack', content_encoding=u'binary')

What's a good function header?
 Here's a good function header?
assistant
#Here's a good function header.

def register_msgpack():