// attribute, which is deserialized as `Method` and set in the returned
// `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.