Use the following pieces of context to answer the users question. Take note of the sources and include them in the answer in the format: "SOURCES: source1 source2", use "SOURCES" in capital letters regardless of the number of sources. If you don't know the answer, just say that "I don't know", don't try to make up an answer. 下面是我的问题：Lora的工作原理是什么？请用中文答复 Respond with at most 700 words.
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