[Python-Dev] Reasons behind misleading TypeError message when passing the wrong number of arguments to a method

Michael Foord fuzzyman at voidspace.org.uk
Thu May 20 01:47:33 CEST 2010

On 20/05/2010 00:42, Giampaolo Rodolà wrote:
>>>> class A:
> ...     def echo(self, x):
> ...             return x
> ...
>>>> a = A()
>>>> a.echo()
> Traceback (most recent call last):
>    File "<stdin>", line 1, in<module>
> TypeError: echo() takes exactly 2 arguments (1 given)
> I bet my last 2 cents this has already been raised in past but I want
> to give it a try and revamp the subject anyway.
> Is there a reason why the error shouldn't be adjusted to state that
> *1* argument is actually required instead of 2?

+1 - I've seen many newbies confused by this error and I sometimes do a 
double-take myself.

All the best,


> --- Giampaolo
> http://code.google.com/p/pyftpdlib
> http://code.google.com/p/psutil
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