Python method's arguments validation, ArgError
When programming in C#
I usually write following arguments validation code:
void Process(object item) {
if (item == null) throw ArgumentNullException();
// code
}
Is it 'Pythonic' to do similar validation in Python
? I really don't want anybody pass 开发者_如何学JAVANone
to Process
method. What type of Python Exception
should I use? (There are no standard ArgError
or something like this)
def Process(item):
if item == None: raise ArgNoneError('item')
# code
Thanks
Usually, you'd just try to make do with the arguments you got -- if someone passes None
to your function it will fail anyway. There is no need to add complexity to your code without any benefit. Quite the contrary -- often such tests prevent your code from working for cases it would work fine wwithout the tests.
If you want to raise some error anyway, use TypeError
-- it is meant for this purpose.
Use TypeError
:
exception TypeError
Raised when an operation or function is applied to an object of inappropriate type. The associated value is a string giving details about the type mismatch.
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