错误：“or”的右操作数从未被评估[无法访问]

Question

我对 if 进行了验证，mypy 告诉我该错误：“or”的右操作数永远不会被评估[无法访问]。

if category is None and (
    category["Description"] is None
    or category["Description"] == ""
):

您可以帮我解决这个问题吗，谢谢

Answer 1

从技术上讲，只有当

category

是一个字典而不是

None

时，第二部分才有意义

if category is not None and 
   ("Description" in category and 
    category["Description"] in [None, '']):
  ...

"Description" in category

确保键

"Description"

存在于字典中

category

。

category["Description"] in [None, ""]

检查

category["Description"]

是否为

None

或

""