input: Write a python function to return the sum of two numbers using the sum_nums method of the Python class.
  assert sum_using_class_method(4, 5) == 9
  assert sum_using_class_method(10, 15) == 25
  assert sum_using_class_method(-3, 3) == 0
output: class NumberOperations:
      @staticmethod
      def sum_nums(a, b):
          return a + b
  
  def sum_using_class_method(a, b):
      return NumberOperations.sum_nums(a, b)