code: def forward(self, input):
      return input.sum(dim=[1, 2, 3])
  
imports: from collections import defaultdict
  import cv2
  import numpy
  import pytest
  import torch
  from torch import nn
  from pytorch_toolbelt.inference import tta
  from pytorch_toolbelt.utils.torch_utils import to_numpy
label_desc: Use image node_id 2 for calling the SumAll obj's underlying member method code with example usage: obj.forward(input) and returns: input