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Date: Mon, 15 Oct 2012 12:42:48 -0400
From: Dave Angel <d@davea.name>
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To: python-list@python.org
Subject: Re: Exception Messages
References: <8b5cb95f-424b-45a8-b19b-42f92f531a75@googlegroups.com> <mailman.2217.1350317845.27098.python-list@python.org> <k5hd7c$emf$1@reader1.panix.com> <507C3B2A.4050506@mrabarnett.plus.com>
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On 10/15/2012 12:34 PM, MRAB wrote:
> On 2012-10-15 17:22, John Gordon wrote:
>> In <mailman.2217.1350317845.27098.python-list@python.org> MRAB
>> <python@mrabarnett.plus.com> writes:
>>
>>> > Why wasn't the message printed out?
>>>
>>> You didn't add a __str__ method:
>>
>>> class PvCamError(Exception):
>>>      def __init__(self, msg):
>>>          self.msg = msg
>>>      def __str__(self):
>>>          return self.msg
>>
>> Wouldn't PvCamError inherit __str__() from Exception?
>>
> Yes, but you've put the message in msg, and Exception doesn't have that
> attribute.
>
> An alternative approach would be:
>
> class PvCamError(Exception):
>     pass
>

Wouldn't another approach be for this __init__() method to call the
base-class __init__() method with whatever data it needs?



-- 

DaveA