Success! Final stack:
  [(Lean.Doc.Syntax.ul
    "ul{"
    [(Lean.Doc.Syntax.li
      "*"
      [(Lean.Doc.Syntax.ul
        "ul{"
        [(Lean.Doc.Syntax.li
          "*"
          [(Lean.Doc.Syntax.para
            "para{"
            [(Lean.Doc.Syntax.text
              (str "\"A1\""))]
            "}")])
         (Lean.Doc.Syntax.li
          "*"
          [(Lean.Doc.Syntax.para
            "para{"
            [(Lean.Doc.Syntax.text
              (str "\"A2\""))]
            "}")])]
        "}")])
     (Lean.Doc.Syntax.li
      "*"
      [(Lean.Doc.Syntax.para
        "para{"
        [(Lean.Doc.Syntax.text (str "\"B\""))]
        "}")
       (Lean.Doc.Syntax.ul
        "ul{"
        [(Lean.Doc.Syntax.li
          "*"
          [(Lean.Doc.Syntax.para
            "para{"
            [(Lean.Doc.Syntax.text
              (str "\"B1\""))]
            "}")])
         (Lean.Doc.Syntax.li
          "*"
          [(Lean.Doc.Syntax.para
            "para{"
            [(Lean.Doc.Syntax.text
              (str "\"B2\""))]
            "}")])]
        "}")])]
    "}")]
All input consumed.