code: def test_single_projection_head(self, device: str = "cpu", seed=0):
      for head_cls in self.heads:
          for (
              in_features,
              hidden_features,
              out_features,
          ) in self.n_features:
              torch.manual_seed(seed)
              if head_cls == DINOProjectionHead:
                  bottleneck_features = hidden_features
                  head = head_cls(
                      in_features,
                      hidden_features,
                      bottleneck_features,
                      out_features,
                  )
              elif head_cls == SimCLRProjectionHead:
                  head = head_cls(
                      in_features,
                      hidden_features,
                      out_features,
                      batch_norm=False,
                  )
              else:
                  head = head_cls(
                      in_features, hidden_features, out_features
                  )
              head = head.eval()
              head = head.to(device)
              for batch_size in [1, 2]:
                  msg = (
                      f"head: {head_cls}"
                      + f"d_in, d_h, d_out = "
                      + f"{in_features}x{hidden_features}x{out_features}"
                  )
                  with self.subTest(msg=msg):
                      x = torch.torch.rand(
                          (batch_size, in_features)
                      ).to(device)
                      with torch.no_grad():
                          y = head(x)
                      self.assertEqual(y.shape[0], batch_size)
                      self.assertEqual(y.shape[1], out_features)
  
file_path: lightly/tests/models/test_ProjectionHeads.py
imports: import unittest
  import torch
  import lightly
  from lightly.models.modules.heads import BarlowTwinsProjectionHead, BYOLPredictionHead, BYOLProjectionHead, DINOProjectionHead, MoCoProjectionHead, MSNProjectionHead, NNCLRPredictionHead, NNCLRProjectionHead, SimCLRProjectionHead, SimSiamPredictionHead, SimSiamProjectionHead, SwaVProjectionHead, SwaVPrototypes, TiCoProjectionHead, VicRegLLocalProjectionHead
label_desc: Use image node_id 2 for calling the TestProjectionHeads obj's underlying member method code with example usage: obj.test_single_projection_head(device, seed) without return types