(motive : Option (Lean.TSyntax `Lean.Parser.Command.docComment) → Sort u_1) →
  (docString? : Option (Lean.TSyntax `Lean.Parser.Command.docComment)) →
    ((docString : Lean.TSyntax `Lean.Parser.Command.docComment) → motive (some docString)) →
      (Unit → motive none) → motive docString?