class_docstr: Mask item sequence for training.
class_docstr_tok: ["Mask","item","sequence","for","training","."]
code: def __init__(self, config):
      self.ITEM_SEQ = config["ITEM_ID_FIELD"] + config["LIST_SUFFIX"]
      self.ITEM_ID = config["ITEM_ID_FIELD"]
      self.MASK_ITEM_SEQ = "Mask_" + self.ITEM_SEQ
      self.POS_ITEMS = "Pos_" + config["ITEM_ID_FIELD"]
      self.NEG_ITEMS = "Neg_" + config["ITEM_ID_FIELD"]
      self.max_seq_length = config["MAX_ITEM_LIST_LENGTH"]
      self.mask_ratio = config["mask_ratio"]
      self.ft_ratio = (
          0 if not hasattr(config, "ft_ratio") else config["ft_ratio"]
      )
      self.mask_item_length = int(self.mask_ratio * self.max_seq_length)
      self.MASK_INDEX = "MASK_INDEX"
      config["MASK_INDEX"] = "MASK_INDEX"
      config["MASK_ITEM_SEQ"] = self.MASK_ITEM_SEQ
      config["POS_ITEMS"] = self.POS_ITEMS
      config["NEG_ITEMS"] = self.NEG_ITEMS
      self.ITEM_SEQ_LEN = config["ITEM_LIST_LENGTH_FIELD"]
      self.config = config
  
imports: import math
  import numpy
  import random
  import torch
  from copy import deepcopy
  from recbole.data.interaction import Interaction, cat_interactions
label_desc: Use image node_id 1 to create a new MaskItemSequence object  with example: obj = MaskItemSequence(config)