GHP - Brep.CreateBlendSurface - How to get or define face0 As BrepFace and edge0 As BrepEdge

I want to create a Blend Surface in GHPython between two single Surfaces.
It seems to me I have to do that with Brep.CreateBlendSurface.
It asks for BrepFace and BrepEdge for both Surfaces.
Can anyone explain how to get or declare those?

Should be yourBrep.Faces[index] and yourBrep.Edges[index]

Thx, I got that.
Now I got stuck with domain.

I can get start and end of it:

print edgeA.Domain.T0
print edgeA.Domain.T1

…but I don’t know how to put it together.

#print edgeA.Domain.Item (0; 1)
#print rc.Geometry.Domain.Interval ()
#print edgeA.Domain.Interval ()
dom_A = edgeA.Domain ( edgeA.Domain.T0, edgeA.Domain.T1)
#dom_A = rc.Geometry.Domain ( edgeA.Domain.T0, edgeA.Domain.T1)
#dom_A = edgeA.Domain ( T0, T1)
#dom_A = edgeA.New ( T0, T1)

BTW
@Michael_Pryor
I found this Site about Surface Tweens (https://www.grasshopper3d.com/photo/tweens?context=user).
Unfortunatly the link doesn’t work anymore.
Can I find this code somewhere?

The link works fine, you have to be a member of milkbox group. Anyway it is outdated as I’ve added all that in Pufferfish.