class_docstr: Load dataset with MOT format, support multi-class MOT.
  
  Args:
      dataset_dir (str): root directory for dataset.
      image_lists (list(str)): mcmot data image lists, muiti-source mcmot dataset.
      data_fields (list): key name of data dictionary, at least have 'image'.
      label_list (str): if use_default_label is False, will load
          mapping between category and class index.
      sample_num (int): number of samples to load, -1 means all.
  
  Notes:
      MCMOT datasets root directory following this:
          dataset/mot
          |——————image_lists
          |        |——————visdrone_mcmot.train  
          |        |——————visdrone_mcmot.val   
          visdrone_mcmot
          |——————images
          |        └——————train
          |        └——————val
          └——————labels_with_ids
                      └——————train
class_docstr_tok: ["Load","dataset","with","MOT","format",",","support","multi-class","MOT",".","Args",":","dataset_dir","(","str",")",":","root","directory","for","dataset",".","image_lists","(","list","(","str",")",")",":","mcmot","data","image","lists",",","muiti-source","mcmot","dataset",".","data_fields","(","list",")",":","key","name","of","data","dictionary",",","at","least","have","'image","'",".","label_list","(","str",")",":","if","use_default_label","is","False",",","will","load","mapping","between","category","and","class","index",".","sample_num","(","int",")",":","number","of","samples","to","load",",","-1","means","all",".","Notes",":","MCMOT","datasets","root","directory","following","this",":","dataset\/mot","|\u2014\u2014\u2014\u2014\u2014\u2014image_lists","|","|\u2014\u2014\u2014\u2014\u2014\u2014visdrone_mcmot.train","|","|\u2014\u2014\u2014\u2014\u2014\u2014visdrone_mcmot.val","visdrone_mcmot","|\u2014\u2014\u2014\u2014\u2014\u2014images","|","\u2514\u2014\u2014\u2014\u2014\u2014\u2014train","|","\u2514\u2014\u2014\u2014\u2014\u2014\u2014val","\u2514\u2014\u2014\u2014\u2014\u2014\u2014labels_with_ids","\u2514\u2014\u2014\u2014\u2014\u2014\u2014train"]
code: def __init__(
      self,
      dataset_dir=None,
      image_lists=[],
      data_fields=["image"],
      label_list=None,
      sample_num=-1,
  ):
      super(MCMOTDataSet, self).__init__(
          dataset_dir=dataset_dir,
          data_fields=data_fields,
          sample_num=sample_num,
      )
      self.dataset_dir = dataset_dir
      self.image_lists = image_lists
      if isinstance(self.image_lists, str):
          self.image_lists = [self.image_lists]
      self.label_list = label_list
      self.roidbs = None
      self.cname2cid = None
  
imports: import os
  import sys
  import cv2
  import glob
  import numpy
  from collections import OrderedDict, defaultdict
  from .dataset import DetDataset, _make_dataset, _is_valid_file
  from ppdet.core.workspace import register, serializable
  from ppdet.utils.logger import setup_logger
label_desc: Use image node_id 1 to create a new MCMOTDataSet object from inherited base classes: DetDataset with example: obj = MCMOTDataSet(dataset_dir, image_lists, data_fields, label_list, sample_num)