Is the punishment for apostasy considered an expiation for it?

It has been established in the Sunnah of the Prophet that the prescribed punishments (Hudud) serve as an expiation for those upon whom they are carried out, and this includes all sins except shirk (associating partners with Allah), because shirk is unforgivable. As for killing the apostate, it is not a hadd (prescribed punishment), but rather a worldly punishment that does not expiate the sin of apostasy. The Imam or his deputy must execute him, and he must be asked to repent before being killed. If he repents, his repentance is accepted. This differs from the prescribed punishments (Hudud), which are not dropped by repentance after the Imam has been informed.