Access Diffuse Color of Vertex

Hi all,

I am trying to get the diffuse color of a Vertex. There is a procedural texture on the object and I need the color on each vertex, if that is possible at all. I do not mean the vertex color, rather than the diffuse color of the material. The coordinates are probably the generated or object one.

What I found out so far was that I need to create a BMesh in order to access the single verts. There seems to be a solution for the old Blender Versions prior to 2.8 which were

bm = bmesh.new()
bm.from_mesh(obj.data)
DCLayer = bm.loops.layers.color["Diffuse Color"]
loopcolour = bm.faces[0].loops[0][DCLayer]

How to get something similar in Blender 2.8+ ? The attribute “Diffuse Color” does not exist there.