Function: advice-function-member-p
advice-function-member-p is a byte-compiled function defined in
nadvice.el.gz.
Signature
(advice-function-member-p ADVICE FUNCTION-DEF)
Documentation
Return non-nil if ADVICE is already in FUNCTION-DEF.
Instead of ADVICE being the actual function, it can also be the name
of the piece of advice.
Source Code
;; Defined in /usr/src/emacs/lisp/emacs-lisp/nadvice.el.gz
(defun advice-function-member-p (advice function-def)
"Return non-nil if ADVICE is already in FUNCTION-DEF.
Instead of ADVICE being the actual function, it can also be the `name'
of the piece of advice."
(advice--member-p advice :use-both function-def))