-- binary
04 00 # version, type
00 20 # length
12 34 56 78 # xid
00 01 # elements[0].type
00 0c # elements[0].length
00 00 00 01 # elements[0].bitmaps[0]
00 00 00 02 # elements[0].bitmaps[1]
00 01 # elements[1].type
00 0c # elements[1].length
00 00 00 03 # elements[1].bitmaps[0]
00 00 00 04 # elements[1].bitmaps[1]
-- python
ofp.message.hello(
    xid=0x12345678,
    elements=[
        ofp.hello_elem_versionbitmap(
            bitmaps=[ofp.uint32(1), ofp.uint32(2)]),
        ofp.hello_elem_versionbitmap(
            bitmaps=[ofp.uint32(3), ofp.uint32(4)])])