Black hole as a storage device?

I'm writing a sci-fi story, and there is a giant autonomous computer planet that constantly gathers resources from around the universe using drones. It stores a super weapon at the core of the planet, inside a black hole that is also used as a main power source for the planet, so as to keep the whole device much more compact and unnoticeable. I wasn't sure how the weapon could be pulled back out, and I was thinking perhaps magnets? I haven't really heard about magnetic fields being affected by gravity, and the magnets power could be supplied by the infinite power that the black hole produces. Could this work in any scenario?