[TxMt] command to renumber snippet tabs?

hi, just wondering if anyone has written a command to renumber the ${1:var} items in a snippet? I find myself doing this quite often when developing a new snippet and it is a bit tedious.

Ideally, the command would allow you write a snippet like this

${n:not sure${n:about} the ${n:order) ${n:yet ${n:but that no longer matters}}

and have the command turn it into

${1:not sure${2:about} the ${3:order) ${4:yet ${5:but that no longer matters}}

as well as coping with

${1:not sure${2:about} the ${3:order) ${n:oops, added this!} ${4:yet ${5:but that no longer matters}}

-->

${1:not sure${2:about} the ${3:order) ${4:oops, added this!} ${5:yet ${6:but that no longer matters}}