Create an existing group of nodes in compositing

Question

I want add to compositing an existing group, but I don’t know what to write to import a existing group (where can I see the available commands for compositing, not bpy..., I mean comp_node... ?). Is it possible to at least switch empty group to existing NodeGroup? I looked through all the answers, nowhere is a working code.

my variant:

import bpy
bpy.context.scene.use_nodes = True
tree = bpy.context.scene.node_tree
comp_node = tree.nodes.new('CompositorNodeGroup')
comp_node = ???????

Answer 1

If you already have a node group then this code will help you and if you want to know how to create node groups this link will help you. How to handle creating a node group in a script?

import bpy
scene = bpy.context.scene
use_nodes = scene.use_nodes
if not use_nodes:
    scene.use_nodes = True
tree = scene.node_tree
nodes = tree.nodes
nodes.clear()
#check if there is already group
new_group = nodes.get('Group')
if not new_group:
    new_group= nodes.new('CompositorNodeGroup')
new_group.node_tree = bpy.data.node_groups['NodeGroup']