input: Write a python function to calculate the total sum of a given list of numbers.
  assert get_total_sum([1, 2, 3, 4, 5]) == 15
  assert get_total_sum([10, 20, 30, 40, 50]) == 150
  assert get_total_sum([5, 7, 9, 8, 6, 4, 3]) == 42
output: def get_total_sum(numbers):
      return sum(numbers)