code: def test_empty_batch(self):
      input = torch.zeros(0, 3, 10, 10, dtype=torch.float32)
      rois = torch.zeros(0, 5, dtype=torch.float32)
      op = ROIAlign((7, 7), 1.0, 0, aligned=True)
      output = op.forward(input, rois)
      self.assertTrue(output.shape == (0, 3, 7, 7))
  
file_path: detectron2/tests/layers/test_roi_align.py
imports: import numpy
  import unittest
  from copy import copy
  import cv2
  import torch
  from fvcore.common.benchmark import benchmark
  from torch.nn import functional
  from detectron2.layers.roi_align import ROIAlign, roi_align
label_desc: Use image node_id 7 for calling the ROIAlignTest obj's underlying member method code with example usage: obj.test_empty_batch() without return types