code: def test_backend_op_config_set_num_tensor_args_to_observation_type(
      self,
  ):
      conf = BackendPatternConfig(torch.add)
      self.assertEqual(
          len(conf._num_tensor_args_to_observation_type), 0
      )
      conf._set_num_tensor_args_to_observation_type(
          self._num_tensor_args_to_observation_type
      )
      self.assertEqual(
          conf._num_tensor_args_to_observation_type,
          self._num_tensor_args_to_observation_type,
      )
  
imports: import torch
  import torch.ao.nn.intrinsic
  import torch.ao.nn.qat
  import torch.ao.nn.quantized.reference
  from torch.testing._internal.common_quantization import QuantizationTestCase
  from torch.ao.quantization.backend_config import BackendConfig, BackendPatternConfig, DTypeConfig, DTypeWithConstraints, ObservationType
  from torch.ao.quantization.fuser_method_mappings import _sequential_wrapper2
  from torch.ao.quantization.fx.quantize_handler import _default_root_node_getter
label_desc: Use image node_id 17 for calling the TestBackendConfig obj's underlying member method code with example usage: obj.test_backend_op_config_set_num_tensor_args_to_observation_type() without return types