How to make a Group Node added for the second time 'single user' (with python)?

Archive Python API
1

I have a script that adds a node group in the blackboard via python.

My problem is that If I call my function to add the same node group again, it will be added again but as a duplicate of the first one.
I want to make it single_user (via code) if it is already been called once in the blackboard. How can I achieve that?

if context.material != None:
    bpy.ops.node.add_node(
        type="ShaderNodeGroup",
        use_transform=True,
        settings=[{"name":"node_tree", "value": "bpy.data.node_groups[\"%s\"]" % node_group_datablock_name}]
        )
    
    # Here is where it doesn't work:
    bpy.ops.nodes.copy(bpy.context.active_node)

Thanks.