input: Write a function to improve the given Python code that calculates the sum of elements of a list. The original function iterates through the list and accumulates the sum. Modify the function to use a more concise approach to achieve the same result. If the input list is empty, the function should return 0.
  assert sum_elements([1, 2, 3, 4, 5])==15
  assert sum_elements([0, 0, 0, 0])==0
  assert sum_elements([-1, -2, -3, -4, -5])==-15
  assert sum_elements([])==0
  assert sum_elements([100])==100
output: def sum_elements(lst):
      return sum(lst)