Assigning shortcuts for Brush modes

HI, I'm an animator and illustrator working in the games industry.

I use the brush modes for the old Flash brush daily, specifically the Normal mode and the Paint Inside mode.

It pains me that I can't set a shortcut to change between modes, so I was looking for ways this could be made possible.

I tried writing a jsfl command to change what I suppose is a variable within the brush tool, but there is no documentation about it (I'm not really surprised).

What I'm asking for is either a specific way to make the brush mode assignable to a shortcut or the modes variable names to write a command and assign a shortcut to that.

Thanks!