input: Write a function to find the three numbers in a list whose sum is closest to zero.
  assert find_3sum_closest_to_0([-1, 2, 1, -4])==(-1, 2, -4)
  assert find_3sum_closest_to_0([1, -3, 2, 4, 5])==(-3, 2, 1)
  assert find_3sum_closest_to_0([-10, -5, -2, 7, 15])==(-5, -2, 7)
output: def find_3sum_closest_to_0(nums):
      nums.sort()
      closest_sum = float('inf')
      closest_triplet = ()
      
      for i in range(len(nums) - 2):
          left, right = i + 1, len(nums) - 1
          while left < right:
              current_sum = nums[i] + nums[left] + nums[right]
              if abs(current_sum) < abs(closest_sum):
                  closest_sum = current_sum
                  closest_triplet = (nums[i], nums[left], nums[right])
              if current_sum < 0:
                  left += 1
              elif current_sum > 0:
                  right -= 1
              else:
                  return (nums[i], nums[left], nums[right])
      
      return closest_triplet