input: def sum_array(array):
      """A function that takes in an array of numbers and returns the sum of all the numbers"""
      return sum(array)
  
  # Test cases
  # sum_array([1, 2, 3]) == 6
  # sum_array([-1, 0, 1]) == 0
  # sum_array([10, 20, 30]) == 60
output:     return sum(array)