comefrom: <qiyuangong>206_Reverse_Linked_List_1.py
code: def reverseList( head):
      if head is None:
          return
      stack = []
      pos = start = head
      while pos is not None:
          stack.append(pos)
          pos = pos.next
      while len(stack) > 0:
          if len(stack) >= 2:
              stack[0].val, stack[-1].val = stack[-1].val, stack[0].val
              stack.pop(0)
              stack.pop()
          else:
              stack.pop()
      return head
masked: def sample_funcname ( var_0 ) :
      if var_0 is None :
          return
      var_2 = [ ]
      var_4 = var_3 = var_0
      while var_4 is not None :
          var_2.append ( var_4 )
          var_4 = var_4.next
      while len ( var_2 ) > 0 :
          if len ( var_2 ) >= 2 :
              var_2 [ 0 ].val , var_2 [ - 1 ].val = var_2 [ - 1 ].val , var_2 [ 0 ].val
              var_2.pop ( 0 )
              var_2.pop ( )
          else :
              var_2.pop ( )
      return var_0
  