input: Write a function to determine the total sum of all elements of a list. Provide the sum as the output.
  
  def calculate_sum_of_list(arr):
      total_sum = 0
      for item in arr:
          total_sum += item
      return total_sum
  
  list1 = [1, 2, 3, 4]
  assert calculate_sum_of_list(list1) == 10
  
  list2 = [5, 7, -3, 2]
  assert calculate_sum_of_list(list2) == 11
  
  list3 = []
  assert calculate_sum_of_list(list3) == 0
  
  list4 = [-1, -2, -3, -4]
  assert calculate_sum_of_list(list4) == -10
output: def calculate_sum_of_list(arr):
      total_sum = 0
      for item in arr:
          total_sum += item
      return total_sum