// `QuantizationResult`. Otherwise, it returns `std::nullopt`.
std::optional<QuantizationResult> GetQuantizationResult(func::CallOp call_op) {
  const StringRef callee_name = call_op.getCalleeAttr().getValue();
  if (!callee_name.starts_with(kQuantizedFuncPrefix)) {
    return std::nullopt;  // `call_op` is not a quantized function call.
  }

  absl::StatusOr<Method> method = GetQuantizationMethod(call_op);

// to represent calling a TF host callback function.
constexpr llvm::StringRef kTfTargetName = "tf.call_tf_function";

// `tf.backend_config` is a DictionaryAttr, JAX2TF sets the value of its
// string attribute `caller_name` to the TF host callback function's name.
constexpr llvm::StringRef kTfBackendConfigAttrName = "tf.backend_config";
constexpr llvm::StringRef kCalledFuncAttrName = "called_func";

}  // namespace

    : public impl::XlaClusterFormationPassBase<XlaClusterFormationPass> {
  void runOnOperation() override;
};

void EncapsulatePartitionedCall(Operation *call_op,
                                mlir::StringAttr callee_name) {
  OpBuilder builder(call_op);
  auto cluster = builder.create<mlir::tf_device::ClusterOp>(
      call_op->getLoc(), call_op->getResultTypes());
  cluster.getBody().push_back(new Block);

    is AnalysisStatementFilter.ConfiguringCallFilter -> statement is FunctionCall && statement.args.singleOrNull() is FunctionArgument.Lambda
    is AnalysisStatementFilter.NamedCallFilter -> statement is FunctionCall && statement.name == callName
    is AnalysisStatementFilter.NotFilter -> !negationOf.shouldAnalyzeStatement(statement, scopes)
    is AnalysisStatementFilter.TopLevelElementFilter -> scopes.last().receiver is ObjectOrigin.TopLevelReceiver
}

    }

    interface ConfiguringCallFilter : AnalysisStatementFilter
    interface TopLevelElementFilter : AnalysisStatementFilter
    interface NamedCallFilter : AnalysisStatementFilter {
        val callName: String
    }

    interface AnalyzeEverythingFilter : AnalysisStatementFilter