input: Write a function to sort an array in ascending order. The function should take the array as input and return the sorted array.
  
  def sort_ascending(array):
    array.sort()
    return array
  
  assert sort_ascending([10, 3, 9, 1, 15, 2])==[1, 2, 3, 9, 10, 15]
output: def sort_ascending(array):
    array.sort()
    return array