why python don't support "extended slice direct assignment" for lists?

[MRAB]

Robert William Hanks wrote:
> why pure python don't support "extended slice direct assignment" for lists?
> 
> today we have to write like this,
> 
>  >>> aList=[0,1,2,3,4,5,6,7,8,9]
>  >>> aList
> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>  >>> aList[::2]= [None]*len(aList[::2])  #or do the math by hand, what's 
> not always possible
>  >>> aList
> [None, 1, None, 3, None, 5, None, 7, None, 9]
> 
> why not accept syntax like this for extended slice
> 
> aList[::2] = None
> 
> when let's say, the left side is a list and the right side is bool, int 
> or float.
> the laborious [nunber]*len(aList[::2]) seens to me less readable when 
> you want to set lost of items of a list to the same number.
> Also correct me if i am wrong, calling len() and building a list to this 
> kind of operation seems a waste.
> 
> Just want some feedback.
> 
When you're assigning to a list slice, why should it duplicate an int
but not a list? Or in general, duplicate something that's not iterable
but not something that is iterable? A string is iterable, so what
should:

 >>> a[ : : 2] = "abcde"

do?

It's just simpler and less surprising the way it is.