Fanfic AOT Levi x Petra

It had been a few weeks after Petra had died. Levi hadn't been the same person ever
since that day and seemed even colder. One day, when he was sitting in his
office, a knock came from the door. Footsteps could be heard, so the person who
knocked walked away right away, but something was placed in front of the door.
Levi stood up. He didn't want to open but he had to. He opened the door and
looked around. A baby was lying in a basket on the ground. It was asleep and
the basket had a note attached to it. This is what the note said:

Dear Corporal,

Excuse us for bothering you with a child since you're so
busy, but this child is yours. We found it and retrieved it to you, so we hope
you will raise it well.