input: Write a function to calculate the sum of all elements in a list. The function should return the total sum of all elements in the list. If the list is empty, the function should return 0.
  def calculate_sum_of_list(arr):
      total_sum = 0
      for item in arr:
          total_sum += item
      return total_sum
  assert calculate_sum_of_list([1, 2, 3, 4])==10
  assert calculate_sum_of_list([5, 5, 5])==15
  assert calculate_sum_of_list([10, -2, 3])==11
  assert calculate_sum_of_list([])==0
  assert calculate_sum_of_list([100])==100
output: def calculate_sum_of_list(arr):
      total_sum = 0
      for item in arr:
          total_sum += item
      return total_sum