Why am I still weeding my yard?

This invention would be a robot gardener that would take the weeds out of your yard while leaving plants you want. The gardener could be very small, and would just chew up the weed, including the root and then take all the remains into the compost.

We were thinking of getting those rental goats, but they would have chewed up all the plants we want in addition to the weeds. So you could also have a robot shepherd that would steer the goat to the weeds and keep it away from the plants that you want to keep.