There's a little quirk with this:

"hello(what(is(this(all(about)))))" 4
get_proparg returned: "all(about)"
Fastpath: "all(about)))))"

"Fastpath" is your solution. It also doesn't behave very well if I $level is a higher number than there already are nested levels - unfortunatedly you never know before how many there are.

Bye
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