input: Write a python function to calculate the sum of numbers in a list.
  assert calculate_sum([2, 7, 8, 4, 5]) == 26
  assert calculate_sum([1, 2, 3, 4, 5]) == 15
  assert calculate_sum([10, -2, 3, -4, 5]) == 12
output: def calculate_sum(numbers):
      return sum(numbers)