docstr: Initiate _count for all object classes
  :param num_classes:
docstr_tok: ["Initiate","_count","for","all","object","classes",":","param","num_classes",":"]
code: def init_count(num_classes):
      """
      Initiate _count for all object classes
      :param num_classes:
      """
      for cls_id in range(num_classes):
          BaseTrack._count_dict[cls_id] = 0
  
imports: import numpy
  from collections import defaultdict
  from collections import deque, OrderedDict
  from ..matching import jde_matching
  from ppdet.core.workspace import register, serializable
  import warnings
label_desc: Use image node_id 3 for calling the BaseTrack obj's underlying member method code with example usage: obj.init_count(num_classes) without return types