Is a 20 gallon tank big enough for an adult ball python?

I agree that a 20 gallon tank isn't big enough and they won't be very comportable in it but ball pythons don't get longer than 20 feet,the longest a female would get to would be 5 - 6 feet and a male would get to about 4 - 5 feet but that's rare! You could use a 30 gallon tank but the best would be a 40 gallon tank for a fully grown ball python!!