[Python-ideas] proposed methods: list.replace / list.indices

[Random832]

On 12/30/2012 10:05 AM, Nick Coghlan wrote:
> The general problem with adding new methods to types rather than
> adding new functions+protocols is that it breaks ducktyping. We can
> mitigate that now by adding the new methods to
> collections.abc.Sequence, but it remains the case that relying on
> these methods being present rather than using the functional
> equivalent will needlessly couple your code to the underlying sequence
> implementation (since not all sequences inherit from the ABC, some are
> just registered).

You know what wouldn't break duck typing? Adding an 
extension-method-like (a la C#) mechanism to ABCs. Of course, the 
problem with that is, what if a sequence implements a method called 
replace that does something else?