In ancient times, snake meant dragon, and green snake meant dragon. Good omen, respect your ancestors, they will bless you with peace and wealth all your life. Snakes are called money strings in geomantic omen, and the descendants of green snakes thrive in cemeteries. If you are not superstitious, it only means that there are snakes there. If you are superstitious, it is a good sign of wealth and peace. There is never a standard answer to this kind of thing, and there is no need to think about it.