Pyplot Fill between vaying color with specific values

plotting
#1

I’d like to fill between two curves varying the color depending on a value using PyPlot

It fills with a single color but I don’t know how to implement cmap or other keyword to fill as a function of a variable

vshax.fill_betweenx(Depth,Vsh,1,where=(Vsh .<= 1),color="red")