typehints>无或留白

Question

使用python3，可以选择使用typehints。在

我的问题是，如果一个函数返回None，应该添加它，还是留空。在

即

def hint(p:str) -> None:
    pass

def no_hint(p:str):
    pass

哪个政治公众人物解决了这个问题？在

Answer 1

显式并且对于返回None的函数，始终包含-> None

这是因为，对于不带参数的函数，类型检查器将假定您根本没有使用类型提示。例如，def foo():是要返回None，还是只是没有提示类型？在

PEP 484 - Type Hints间接地解决了这个问题：

Note that the return type of __init__ ought to be annotated with -> None. The reason for this is subtle. If __init__ assumed a return annotation of -> None, would that mean that an argument-less, un-annotated __init__ method should still be type-checked? Rather than leaving this ambiguous or introducing an exception to the exception, we simply say that __init__ ought to have a return annotation; the default behavior is thus the same as for other methods.