func_code: def swap(a, i, j):
      tmp = a[i]
      a[i] = a[j]
      a[j] = tmp
      return a[i], a[j]
  
  
  def reverse(a):
      i = 0
      j = len(a) - i - 1
      while i < len(a) / 2:
          swap(a, i, j)
          i = i + 1
      return a