doc:   [
    DocGroup({"tag": "h2"}, [
        DocChars("4"), DocGroup({"client": "right", "tag": "caret"}, []),
        DocChars("go 15")
    ]),
    DocGroup({"tag": "p"}, [
        DocChars("7 ")
    ]),
    DocGroup({"tag": "h2"}, [
        DocGroup({"tag": "caret", "client": "middle"}, []),
        DocChars(" 4"), DocGroup({"tag": "caret", "client": "left"}, []),
        DocChars("72r   0H7ello worldui 5Jt 2s7  ul  ")
    ]),
    DocGroup({"tag": "p"}, [
        DocChars("c6 P6  XXm 4QsWhat\'s up with you?")
    ])
]

a_del: [
    DelWithGroup([
        DelSkip(1), DelWithGroup([]),
        DelSkip(5)
    ]),
    DelWithGroup([
        DelSkip(2)
    ]),
    DelGroup([
        DelSkip(39)
    ])
]
a_add: [
    AddWithGroup([
        AddSkip(1), AddWithGroup([]),
        AddSkip(5)
    ]),
    AddWithGroup([
        AddSkip(2)
    ]),
    AddGroup({"tag": "p"}, [
        AddSkip(39)
    ])
]

b_del: [
    DelWithGroup([
        DelSkip(1), DelWithGroup([]),
        DelSkip(5)
    ]),
    DelWithGroup([
        DelSkip(2)
    ]),
    DelGroup([
        DelSkip(39)
    ])
]
b_add: [
    AddWithGroup([
        AddSkip(1), AddWithGroup([]),
        AddSkip(5)
    ]),
    AddWithGroup([
        AddSkip(2)
    ]),
    AddGroup({"tag": "h2"}, [
        AddChars(" ")
    ]),
    AddGroup({"tag": "bullet"}, [
        AddGroup({"tag": "p"}, [
            AddSkip(39)
        ])
    ])
]