newbie: python list integer not parseable

just a few lines of my code. I’m trying to assign vertices to a VertexGroup, but somehow python returns: “python list integer not parseable”

#  --- assign the vertices to the groups
    for i in range(0,3):
        # ---  create vertex groups
        name = "hor_%s"%i
        me.addVertGroup(name)

        # ---  select and assign the vertices
        vertices = [me.verts[i*3],me.verts[i*3+1],me.verts[i*3+2]]
        me.assignVertsToGroup(name, vertices,1.0, "add")

what am i doing wrong?

SOLVED

should have been a bit more watchful when reading the API. I don’t need a list of vertices, but a list of vertex indices …