input: Write a function to calculate the total sum of all elements in a given list. If the input list is empty, the function should return 0.
  assert calculate_total_sum([1, 9, 3, 5]) == 18
  assert calculate_total_sum([]) == 0
  assert calculate_total_sum([0, 0, 0]) == 0
  assert calculate_total_sum([-1, -3, -5]) == -9
  assert calculate_total_sum([1, 2, 3, 4, 5]) == 15
output: def calculate_total_sum(lst):
      return sum(lst)