What the Pythons docs means by "container" ?

[Mark Lawrence]

On 19/02/2015 10:59, perfectican wrote:
> in duck-typing, any objects can acts as Container. but only difference is type that we need to consider as a Container or not.
>

This comment makes no sense to me at all.  Could you please rephrase it, 
preferably supplying some context at the same time.

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence