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