code: def test_backend_op_config_set_observation_type(self):
      conf = BackendPatternConfig(torch.nn.Linear)
      self.assertEqual(
          conf.observation_type,
          ObservationType.OUTPUT_USE_DIFFERENT_OBSERVER_AS_INPUT,
      )
      conf.set_observation_type(
          ObservationType.OUTPUT_SHARE_OBSERVER_WITH_INPUT
      )
      self.assertEqual(
          conf.observation_type,
          ObservationType.OUTPUT_SHARE_OBSERVER_WITH_INPUT,
      )
  
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 8 for calling the TestBackendConfig obj's underlying member method code with example usage: obj.test_backend_op_config_set_observation_type() without return types