input: Write a python function to calculate the sum of the elements in a list.
  assert calculate_sum([1, 2, 3, 4, 5])==15
  assert calculate_sum([10, 20, 30, 40])==100
  assert calculate_sum([0, -1, 1, 2, -2])==0
output: def calculate_sum(lst):
      return sum(lst)