Applescript for apfs encrypted volume to get to the password screen

I have an encrypted apfs volume named TEST (path is /Volumes/TEST) and would like an AppleScript that will bring up the dialog box asking for the password. I do not want it mounted, just the dialog box for me to enter password.

I can successfully unmount it with this after entering UUID:

do shell script "diskutil unmount UUID"

If I use the following

do shell script "diskutil apfs unlockvolume UUID"

I get this error:

Thanks