input: Write a function to calculate the sum of the elements in a given list.
  assert sum_elements([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 55
  assert sum_elements([10, 20, 30, 40, 50]) == 150
  assert sum_elements([5, 10, 15, 20, 25]) == 75
output: def sum_elements(lst):
      return sum(lst)