input: def sum_sequence(sequence: List[int]) -> int:
      """Calculate the sum of a sequence of integers.
      >>> sum_sequence([1, 2, 3, 4, 5])
      15
      >>> sum_sequence([-1, 0, 1])
      0
      """
      sum = 0
      for num in sequence:
          sum += num
      return sum
output:     sum = 0
      for num in sequence:
          sum += num
      return sum