Objective-C方法，它们唯一的参数是NSError对象引用，我应该如何命名它们？

I was designing a class and I realize that I've got several methods that the only parameter they have is the output parameter for errors. The problem is how should I name this methods, because they can get very confusing. I've been reading the Apple's Code Guidelines and it saids nothing about this. Here is an example:I was designing a class and I realize that I've