func_code: def swap(a, i, j):
      tmp = a[i]
      a[i] = a[j]
      a[j] = tmp
  
  
  def reverse(a):
      z = 0
      x = len(a)
      if len(a) % 2 != 0:
          while z < len(a) / 2:
              swap(a, z, x)
              z = z + 1
              x = x - 1
      else:
          while z < len(a) / 2 + 1:
              swap(a, z, x)
              z = z + 1
              x = x - 1