#Braingolf, 1 byte

 +

[Try it online!](https://tio.run/##SypKzMxLz89J@/9f@/9/AA)

[Try it doubled!](https://tio.run/##SypKzMxLz89J@/9fW/v/fwA)

I don't know how this works, most important it does!