code: def next_id(cls_id):
      BaseTrack._count_dict[cls_id] += 1
      return BaseTrack._count_dict[cls_id]
  
imports: import numpy
  from collections import defaultdict
  from collections import deque, OrderedDict
  from ..matching import jde_matching
label_desc: Use image node_id 2 for calling the BaseTrack obj's underlying member method code with example usage: obj.next_id(cls_id) and returns: BaseTrack