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

[Greg Ewing]

Giampaolo Rodolà wrote:

> "unbound method echo() must be called with A instance as first
> argument (got nothing instead)"
> 
> It talks about "arguments" while no arguments are actually involved in
> the problem: just a class I forgot to initialize.

It's hard to see how this could be improved. If you had been
intending to call an unbound method, the comment about arguments
would have been relevant -- you were supposed to supply one
but didn't. Python is unable to read your mind and figure out
that you really meant something else altogether.

BTW, unbound methods no longer exist in Py3, so you would get
the standard message about incorrect number of arguments
instead. Not sure whether that's better or worse in this
situation.

-- 
Greg