Newbie question.. how to load modules with a dynamic name?

[Ron Scinta]

> >  This does not work alas....
> >  >>> mymod = "ptw"
>
> >>> exec('import ' + mymod)
>
> ds

OK, but how then do I reference the dynamic module by name?

mymod. (The period does not help here, still thinks I am using the string
class instead of my imported module)....

 Is there a way to alias the module name at this point?