input: Write a python function to sum the odd elements in a list.
  assert sum_odd_elements([2, 3, 4, 5, 6]) == 8
  assert sum_odd_elements([1, 2, 3, 4, 5, 6]) == 9
  assert sum_odd_elements([10, 21, 32, 43, 54]) == 64
output: def sum_odd_elements(lst):
      return sum(x for x in lst if x % 2 != 0)