input: Write a function that takes an array and sorts it in ascending order.
  
  def sort_ascending(array):
    array.sort()
    return array
  
  assert sort_ascending([10, 3, 9, 1, 15, 2])==[1, 2, 3, 9, 10, 15]
  assert sort_ascending([5, 2, 8, 12, 1])==[1, 2, 5, 8, 12]
  assert sort_ascending([])==[]
  assert sort_ascending([1])==[1]
  assert sort_ascending([7, 3, 3, 3, 5])==[3, 3, 3, 5, 7]
output: def sort_ascending(array):
    array.sort()
    return array