SD4F: (exist? procedure-**maximum**-arity)

[Blake Shaw]

Hiya Guilers,

I've just started Sussman & Hanson's new book "Software Design for Flexibility" 
and am trying to translate one of the functions from MIT-Scheme to Guile:

#+BEGIN_SRC scheme
(define (get-arity proc)
  (or (hash-table-ref/default arity-table proc #f)
      (let ((a (procedure-arity proc))) ;arity not in table
        (assert (eqv? (procedure-arity-min a)
                      (procedure-arity-max a)))
        (procedure-arity-min a))))

(define arity-table (make-weak-key-hash-table))
#+END_SRC

So far this has lead me to these associations:
|------------------------------+--------------------------+-------------------------|
| MIT                          | Guile                    | Comments            
    |
|------------------------------+--------------------------+-------------------------|
| procedure-arity              | arity                    |                     
    |
|------------------------------+--------------------------+-------------------------|
| hash-table-set!              | hashq-set!               | possibly 
=hash-set!=    |
|------------------------------+--------------------------+-------------------------|
| hash-table-ref/default       | hashq-ref                | possibly =hash-ref= 
    |
|                              |                          | or 
=hash-get-handle=    |
|------------------------------+--------------------------+-------------------------|
| make-key-weak-eqv-hash-table | make-weak-key-hash-table | ∃(module) 
w/eqv-hash?   |
|                              |                          | think I saw it 
before   |
|------------------------------+--------------------------+-------------------------|
| assert                       | assert                   | in (rnrs base)      
    |
|                              | &assertion               | + (ice-9 
exceptions)    |
|                              | assert-macro             | + in (debugging 
assert) |
|------------------------------+--------------------------+-------------------------|
| procedure-arity-min          | procedure-minimum-arity  |                     
    |

resulting in this translation of the function:

#+BEGIN_SRC scheme
 (define (get-arity proc)
    (or (hashq-ref arity-table proc #f)
        (let ((a (arity proc)))
          (assert (eqv? (procedure-minimum-arity a)
                        (**procedure-minimum-arity** a)))
          (procedure-minimum-arity a))))
#+END_SRC 

So now I'm just left with figuring out a function for getting the 
**maximum**[1] arity of a procedure, but I'm unsure how to go about this.

I'm a sorta-new schemer and a very new guiler, so I'm unsure where to look... 
any advice would be appreciated![2]

Thanks & happy hacking,
Blake

[1] double earmuffs to emphasize its a function I need but dont have
[2] there is this inquiry already posted, but there was no conclusion 
https://mail.gnu.org/archive/html/guile-user/2021-05/msg00044.html 

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