class_docstr: Test the Regnet FSDP model in comparison with the DDP Regnet
  to verify that both converge to the same losses
code: def test_valid_depths(self) -> None:
      config = self._create_model_config(depth=18)
      model = build_model(config["MODEL"], config["OPTIMIZER"])
      print(self._get_number_parameters(model))
  
      config = self._create_model_config(depth=34)
      model = build_model(config["MODEL"], config["OPTIMIZER"])
      print(self._get_number_parameters(model))
  
      config = self._create_model_config(depth=50)
      model = build_model(config["MODEL"], config["OPTIMIZER"])
      print(self._get_number_parameters(model))
  
file_path: vissl/tests/test_resnext.py
imports: import unittest
  from vissl.models import build_model
  from vissl.optimizers import *
  from vissl.utils.hydra_config import compose_hydra_configuration, convert_to_attrdict
label_desc: Use image node_id 3 for calling the TestResNeXt obj's underlying member method code with example usage: obj.test_valid_depths() without return types