unified attributes. For example, `_tpu_replicate="cluster"` in the
    following code

    ```mlir

      tf_device.return %1 : tensor<?x!tf_type.string>
    }, {

      }, {
        "tf.Yield"() : () -> ()
      }) {is_stateless = false} : (tensor<i1>) -> ()
      tf_device.return

    // expected-remark@above {{ID: 2}}
    tf_device.return %2#0, %2#1 : tensor<i32>, tensor<i32>
    // expected-remark@above {{ID: 3}}

      attrs.push_back(
          b.getNamedAttr("_xla_compile_device_type",
                         b.getStringAttr(specs.xla_compile_device_type)));
    }
    attrs.push_back(b.getNamedAttr("allow_soft_placement",
                                   b.getBoolAttr(specs.enable_soft_placement)));
  } else {
    // Collects the argument and return nodes by looking up the node names
    // specified by the user.