离散数学知识点总结（7）：谓词逻辑（一阶逻辑）：个体词、谓词、量词、特性谓词；特性谓词的常用场景

虹野梦:

请问这是为什么？pip install -r requirements.txt

Collecting cached_property (from -r requirements.txt (line 1))

Cache entry deserialization failed, entry ignored

Could not fetch URL https://pypi.tuna.tsinghua.edu.cn/simple/cached-property/: There was a problem confirming the ssl certificate: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:748) - skipping

Could not find a version that satisfies the requirement cached_property (from -r requirements.txt (line 1)) (from versions: )

No matching distribution found for cached_property (from -r requirements.txt (line 1))