input: Develop a Python function that accepts a non-empty list of integers and returns the sum of the even elements that are found at odd indices.
  assert add([4, 88]) == 88
  assert add([4, 5, 6, 7, 2, 122]) == 122
  assert add([4, 0, 6, 7]) == 0
  assert add([4, 4, 6, 8]) == 12
output:     
      total = 0
      for index in range(1, len(lst), 2):
          if lst[index] % 2 == 0:
              total += lst[index]
      return total
  