input: Write a python function to create a Summator class that takes two numbers and returns their sum.
  assert Summator(3, 5).get_sum() == 8
  assert Summator(10, 20).get_sum() == 30
  assert Summator(-1, 1).get_sum() == 0
output: class Summator:
      def __init__(self, a, b):
          self.a = a
          self.b = b
  
      def get_sum(self):
          return self.a + self.b