
doc:   [
    DocGroup({"tag": "bullet"}, [
        DocGroup({"tag": "pre"}, [
            DocGroup({"client": "a", "tag": "caret"}, []),
            DocChars(" g")
        ]),
        DocGroup({"tag": "h3"}, [
            DocChars(" OK "), DocGroup({"tag": "caret", "client": "b"}, []),
            DocChars("lokWhat\'s up with you?")
        ])
    ])
]

a_del: [
    DelWithGroup([
        DelGroup([
            DelGroup([]),
            DelChars(2)
        ])
    ])
]
a_add: [
    AddWithGroup([
        AddGroup({"tag": "h3"}, [
            AddChars(" "), AddGroup({"tag": "caret", "client": "a"}, [])
        ])
    ])
]

b_del: [
    DelGroup([
        DelWithGroup([
            DelWithGroup([]),
            DelSkip(2)
        ]),
        DelWithGroup([
            DelSkip(1), DelChars(3), DelGroup([])
        ])
    ])
]
b_add: [
    AddWithGroup([
        AddWithGroup([]),
        AddSkip(2)
    ]),
    AddWithGroup([
        AddSkip(1), AddChars("x"), AddGroup({"client": "b", "tag": "caret"}, []),
        AddChars("2")
    ])
]
