import bpy

bpy.ops.object.select_all(action="DESELECT")
this_object = bpy.data.objects["Cube"]
modifier_status = bpy.ops.object.modifier_add_node_group(asset_library_type="ESSENTIALS", asset_library_identifier="", relative_asset_identifier="geometry_nodes\\smooth_by_angle.blend\\NodeTree\\Smooth by Angle")