code: def __init__(self, image_dir, anno_file, multi_scale=True):
      self.image_dir = image_dir
      self.anno_file = anno_file
      self.multi_scale = multi_scale
      self.clsid2catid, self.catid2name = get_categories("widerface")
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import sys
  import json
  import paddle
  import numpy
  import typing
  from collections import defaultdict
  from pathlib import Path
  from .map_utils import prune_zero_padding, DetectionMAP
  from .coco_utils import get_infer_results, cocoapi_eval
  from .widerface_utils import face_eval_run
  from ppdet.data.source.category import get_categories
  from ppdet.modeling.rbox_utils import poly2rbox_np
  from ppdet.utils.logger import setup_logger
label_desc: Use image node_id 1 to create a new WiderFaceMetric object from inherited base classes: Metric with example: obj = WiderFaceMetric(image_dir, anno_file, multi_scale)