Create a function that takes a list of numbers and returns the sum of its cubes.
sum_of_cubes([1, 5, 9]) ➞ 855
# Since 1^3 + 5^3 + 9^3 = 1 + 125 + 729 = 855
sum_of_cubes([3, 4, 5]) ➞ 216
sum_of_cubes([2]) ➞ 8
sum_of_cubes([]) ➞ 0
If given an empty list, return 0.