Somebody shovelled my steps overnight and I left hot chocolate in return

It snowed forty centimeters overnight and I woke up late to a clear path from my door to the street. The steps and the sidewalk had been shovelled all the way to the corner. I looked up and down the street and nobody was around, only boot prints. I left a thermos of hot chocolate on the railing. It was gone by afternoon, rinsed, back on my doorstep, with a mitten on top. The mitten is not mine. I have kept it. I think that is the arrangement.