gistfile1.rkt

(require ometa)

(define-ometa-namespace parser)

(define-ometa py-parser
  (literal (seq (list (atom lit) (bind value (atom anything)))
                (-> value))))

(omatch
 py-parser
 literal
 '(lit 1)
 parser)

in fact for something like you want above, you don't even have to touch Racket code, but rather define a helper rule or grammar that defines the kind of list you mean in your code. So you can and probably should stay in the realm of OMeta for that one.