comefrom: <qiyuangong>086_Partition_List_1.py
code: def partition( head, x):
      if head is None:
          return None
      less = lesshead = None
      last = pos = head
      while pos is not None:
          if pos.val < x:
              if lesshead is None:
                  lesshead = pos
              else:
                  less.next = pos
              less = pos
              if head == pos:
                  last = head = pos.next
              else:
                  last.next = pos.next
          else:
              last = pos
          pos = pos.next
      if lesshead is not None:
          less.next = head
      else:
          lesshead = head
      return lesshead
masked: def sample_funcname ( var_0 , var_1 ) :
      if var_0 is None :
          return None
      var_4 = var_3 = None
      var_6 = var_5 = var_0
      while var_5 is not None :
          if var_5.val < var_1 :
              if var_3 is None :
                  var_3 = var_5
              else :
                  var_4.next = var_5
              var_4 = var_5
              if var_0 == var_5 :
                  var_6 = var_0 = var_5.next
              else :
                  var_6.next = var_5.next
          else :
              var_6 = var_5
          var_5 = var_5.next
      if var_3 is not None :
          var_4.next = var_0
      else :
          var_3 = var_0
      return var_3
  