input: Write a function to implement an improvement for the given Python code that finds the sum of elements in a list using a more concise approach. If the input list is empty, return 0.
  assert sum_elements([1, 2, 3, 4, 5])==15
  assert sum_elements([10, 20, 30])==60
  assert sum_elements([-1, 0, 1])==0
  assert sum_elements([])==0
output: def sum_elements(lst):
      return sum(lst) if lst else 0