'Mark import names as needing to be re-written.
The named module or package as well as any nested modules will
be re-written on import.'

def mark_rewrite(self, *names):

    already_imported = set(names).intersection(set(sys.modules))
    if already_imported:
        for name in already_imported:
            if (name not in self._rewritten_names):
                self._warn_already_imported(name)
    self._must_rewrite.update(names)
