input: Write a function to calculate the total sum of all elements in the given list. The function should iterate through each element in the list and accumulate the sum.
  assert calculate_total_sum([1, 9, 3, 5])==18
  assert calculate_total_sum([0, 0, 0, 0])==0
  assert calculate_total_sum([-1, -2, -3, -4])==-10
  assert calculate_total_sum([7])==7
  assert calculate_total_sum([])==0
output: def calculate_total_sum(lst):
      total = 0
      for num in lst:
          total += num
      return total