我应该在Python中提出错误/非法参数组合的异常？ [英] Which exception should I raise on bad/illegal argument combinations in Python?

问题描述

我想知道在Python中指示无效参数组合的最佳实践。我遇到了一些这样的功能：

  def import_to_orm（name，save = False，recurse = 
 $ b
：参数名称：要导入的外部实体的名称
：param save：返回前保存ORM对象
：param recurse：因为
需要原始对象有一个关键字，所以save必须是
`True`用于递归为'True'
：raise 
 
 $
 
 $ / code $ <$ $ $ $ $ $ $ $ $ $ > 
 
 
唯一的烦恼是每个包都有自己的，通常略有不同 BadValueError 。我知道在Java中存在 java.lang.IllegalArgumentException   - 很明白，每个人都将创建自己的 BadValueError  s在Python或还有另一个首选方法？
解决方案
我只是提高 ValueError ，除非您需要更具体的例外。
  def import_to_orm（name，save = False，recurse = False）：
如果递归而不保存：
 raise ValueError（save must be True如果递归为True）
  
真的没有意义， class BadValueError ValueError）：pass   - 您的自定义类与 ValueError ，那么为什么不使用它？
 
I was wondering about the best practices for indicating invalid argument combinations in Python. I've come across a few situations where you have a function like so:
def import_to_orm(name, save=False, recurse=False):
    """
    :param name: Name of some external entity to import.
    :param save: Save the ORM object before returning.
    :param recurse: Attempt to import associated objects as well. Because you
        need the original object to have a key to relate to, save must be
        `True` for recurse to be `True`.
    :raise BadValueError: If `recurse and not save`.
    :return: The ORM object.
    """
    pass
The only annoyance with this is that every package has its own, usually slightly differing BadValueError. I know that in Java there exists java.lang.IllegalArgumentException -- is it well understood that everybody will be creating their own BadValueErrors in Python or is there another, preferred method?
解决方案
I would just raise ValueError, unless you need a more specific exception..
def import_to_orm(name, save=False, recurse=False):
    if recurse and not save:
        raise ValueError("save must be True if recurse is True")
There's really no point in doing class BadValueError(ValueError):pass - your custom class is identical in use to ValueError, so why not use that?

                        
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