On 20/10/2017 10:09, Thomas Jollans wrote: > Read the source if you want to know how this is done. > https://github.com/python/cpython/blob/master/Lib/copy.py#L111 Good, informative comment block at the top of the type that you don't see often. Usually they concern themselves with licensing or with apportioning credits. Still, copying looks pretty complicated... -- bartc