class_docstr: Simple operator test
code: def setUp(self) -> None:
      img_pil = Image.open(test_image).convert("RGB")
      self.img_tensor = torchvision.transforms.ToTensor()(img_pil)
      self.images = [self.img_tensor.to(device)]
      self.model_name = "fasterrcnn_resnet50_fpn"
  
file_path: towhee/tests/unittests/operators/test_pytorch_object_detection_operator.py
imports: import unittest
  import torch
  import torchvision
  from pathlib import Path
  from towhee.utils.pil_utils import PILImage
  from tests.unittests.mock_operators import PYTORCH_OBJECT_DETECTION_OPERATOR_PATH, load_local_operator
label_desc: Use image node_id 1 for calling the TestOperator obj's underlying member method code with example usage: obj.setUp() without return types