code: def test_backend_op_config_set_input_type_to_index(self):
      conf = BackendPatternConfig(torch.addmm)
      self.assertEqual(len(conf._input_type_to_index), 0)
      conf._set_input_type_to_index(self._input_type_to_index)
      self.assertEqual(
          conf._input_type_to_index, self._input_type_to_index
      )
  
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 18 for calling the TestBackendConfig obj's underlying member method code with example usage: obj.test_backend_op_config_set_input_type_to_index() without return types