How to create a double dashed bar across the PianoStaff in the middle of a measure?

[Volodymyr Prokopyuk]

Hello,

How to create a double dashed bar across the PianoStaff in the middle of a
measure to indicate Fine?

I can successfully create the following bars across the PianoStaff

   - Double solid bar with \bar "||"
   - Single dashed bar with \bar "!"

I've tried with no success \bar "!!" and some variations of \defineBarLine
to create a double dashed bar across the PianoStaff in the middle of a
measure to indicate Fine. Could you, please, help me?

I'm using lilypond v2.23.11.

Thank you very much in advance! Vlad