generator function that yield from a list

[buran]

@snippsat, thanks, but my question is more or less theoretical (please check also the SO)
basically, I ask I ask if we have (pseudocode)

def spam():
    for egg in <SOME LIST/TUPLE OBJECT HERE, e.g. returned by some function or method like str.split()>:
       yield egg

does python evaluate the list/tuple when creating the generator function I.e. create the whole list in memory or it is evaluated lazy only when yield next value. I think it's the later