GH Graph Mapper from Python

@piac @DavidRutten

I am trying to access Graph Mapper input and output from a Python component. I found the following two bits of information:

https://discourse.mcneel.com/t/graph-mapper-in-python/8277
https://www.grasshopper3d.com/forum/topics/script-control-of-graphmapper

I am able to get the Graph Mapper object I am interested in as follows:

import Grasshopper as gh

graph_mapper_nick = "MyGraphMapper"

for obj in ghenv.Component.OnPingDocument().Objects:
    if type(obj) == gh.Kernel.Special.GH_GraphMapper and str(obj.NickName) == graph_mapper_nick:
        print(type(obj))

I cannot find documentation for GH_GraphMapper. May you point me in the right direction or explain how I can pass in values to the Graph Mapper and read the results back out.

Using a function in Python is not an option, I specifically need the flexibility of the Graph Mapper. Many thanks in advance for your help.