code: def test_netvlad(self):
      # x = torch.rand(1, 3, 256, 436)
      output = self.model(self.img_tensor)
      self.assertEqual(self.num_clusters * self.dim, output.shape[1])
  
file_path: towhee/tests/unittests/models/layers/test_netvlad.py
imports: import unittest
  import torchvision
  from pathlib import Path
  from towhee.utils.pil_utils import PILImage
  from towhee.models.layers.netvlad import NetVLAD, EmbedNet
  from torchvision.models import resnet18
  from torch import nn
label_desc: Use image node_id 2 for calling the NetvladTest obj's underlying member method code with example usage: obj.test_netvlad() without return types