input: Write a function to find the second smallest element in a list.
  assert secondSmallestElement([10, 5, 1, 8, 7]) == 5
  assert secondSmallestElement([4, 3, 2, 1]) == 2
  assert secondSmallestElement([15, 11, 10, 12, 13]) == 11
output: def secondSmallestElement(lst):
      if len(lst) < 2:
          return None  # Handle case where there are fewer than 2 elements
  
      first, second = float('inf'), float('inf')
      for num in lst:
          if num < first:
              first, second = num, first
          elif first < num < second:
              second = num
  
      return second