code: def _get_backend_op_config1(self):
      return (
          BackendPatternConfig((torch.nn.Linear, torch.nn.ReLU))
          .set_observation_type(
              ObservationType.OUTPUT_USE_DIFFERENT_OBSERVER_AS_INPUT
          )
          .add_dtype_config(self.dtype_config1)
          .add_dtype_config(self.dtype_config2)
          .set_root_module(torch.nn.Linear)
          .set_qat_module(nnqat.Linear)
          .set_reference_quantized_module(nnqr.Linear)
          .set_fused_module(nni.LinearReLU)
          .set_fuser_method(self._fuser_method)
      )
  
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 4 for calling the TestBackendConfig obj's underlying member method code with example usage: obj._get_backend_op_config1() and returns: BackendPatternConfig