请翻译以下内容：
Lastly, we include
an Oracle retriever, which serves two purposes: first, to identify the potential for performance
improvement through more efficient retrievers, and second, to assist users who know which API
to use but may need to help invoking it. In all cases, when a retriever is used, it is appended to
the user’s prompt as follows:  Use this API documentation for reference:
. The dataset for these evaluations is detailed in Sec 3. We emphasize
that we have maintained a holdout test set on which we report our findings. The holdout test set was
created by dividing the self-instruct dataset’s instruction, API pairs into training and testing sets.
 The letter g should appear at least 28 times.
user