如何跳过 crossref 和语义分析?

By default, SEMANTIC_SCHOLAR_API_KEY, CROSSREF_MAILTO, and CROSSREF_API_KEY are turned on, and I want to do everything offline - some of the papers and sources I use are not indexed there, and I don't want to mess with setting up the API keys (I'm actually a noob). How can I turn off the check for these variables and everything they entail?