input: Write a python function to calculate the sum of a list of numbers using a class method.
  assert CalcListSum([2, 3, 5, 7]).get_sum() == 17
  assert CalcListSum([1, 2, 3, 4]).get_sum() == 10
  assert CalcListSum([0, 0, 0, 0]).get_sum() == 0
  assert CalcListSum([-1, -2, -3, -4]).get_sum() == -10
output: class CalcListSum:
      def __init__(self, numbers):
          self.numbers = numbers
  
      def get_sum(self):
          return sum(self.numbers)