Print empty/NIL defgeneric/defmethod arglists prettily

SBCL is good at printing quoted Lisp forms, and I sometimes use it as a code formatter. It's especially good with DEFUN forms*

(print '(defun foo ()
         (multiple-value-bind (result)
             (+ 1 2 3)
           (+ result 88))))

(DEFUN FOO ()
  (MULTIPLE-VALUE-BIND (RESULT)
      (+ 1 2 3)
    (+ RESULT 88)))

But it doesn't work with defmethod/defgeneric/defclass, especially with their arglists*

(print '(defmethod foo ()
         (multiple-value-bind (result)
             (+ 1 2 3)
           (+ result 88))))

(DEFMETHOD FOO NIL
           (MULTIPLE-VALUE-BIND
            (RESULT) (+ 1 2 3)
            (+ RESULT 88)))

(print '(defclass foo ()
         ((a :initform 4)
          (b :accessor b
             :initarg :b))))

(DEFCLASS FOO NIL
          ((A :INITFORM 4)
           (B :ACCESSOR B :INITARG :B)))

The same thing:
- empty argument/superclass list is printed as NIL.
- The body is off, as if it's a generic list printing.

Would be nice to have arglist/superclasses as () and properly indented body, like

(DEFMETHOD FOO ()
    (MULTIPLE-VALUE-BIND
          (RESULT) (+ 1 2 3)
      (+ RESULT 88)))

(DEFCLASS FOO ()
  ((A :INITFORM 4)
   (B :ACCESSOR B :INITARG :B)))

I understand that this is likely quite an atypical use-case, so not urging or requiring any action. Feel free to close if it's a non-goal.

All the forms are printed with
- *print-right-margin* set to 40
- on SBCL 2.3.5
- on machine uname Linux paranoidal 6.4.16 #1 SMP PREEMPT_DYNAMIC 1 x86_64 GNU/Linux
- with *features*
(CFFI-FEATURES:FLAT-NAMESPACE
 CFFI-FEATURES:X86-64
 CFFI-FEATURES:UNIX :CFFI
 CFFI-SYS::FLAT-NAMESPACE
 ALEXANDRIA::SEQUENCE-EMPTYP :QUICKLISP
 :ASDF3.3 :ASDF3.2 :ASDF3.1 :ASDF3
 :ASDF2 :ASDF :OS-UNIX
 :NON-BASE-CHARS-EXIST-P :ASDF-UNICODE
 :ARENA-ALLOCATOR :X86-64 :GENCGC
 :64-BIT :ANSI-CL :COMMON-LISP :ELF
 :IEEE-FLOATING-POINT :LINUX
 :LITTLE-ENDIAN
 :PACKAGE-LOCAL-NICKNAMES
 :SB-CORE-COMPRESSION :SB-LDB
 :SB-PACKAGE-LOCKS :SB-THREAD
 :SB-UNICODE :SBCL :UNIX)