code: def download(self, tarDir = None, imgIds = [] ):
          '''
          Download COCO images from mscoco.org server.
          :param tarDir (str): COCO results directory name
                 imgIds (list): images to be downloaded
          :return:
          '''
          if tarDir is None:
              print('Please specify target directory')
              return -1
          if len(imgIds) == 0:
              imgs = self.imgs.values()
          else:
              imgs = self.loadImgs(imgIds)
          N = len(imgs)
          if not os.path.exists(tarDir):
              os.makedirs(tarDir)
          for i, img in enumerate(imgs):
              tic = time.time()
              fname = os.path.join(tarDir, img['file_name'])
              if not os.path.exists(fname):
                  urlretrieve(img['coco_url'], fname)
              print('downloaded {}/{} images (t={:0.1f}s)'.format(i, N, time.time()- tic)f download(self, tarDir = None, imgIds = [] ):
          '''
          Download COCO images from mscoco.org server.
          :param tarDir (str): COCO results directory name
                 imgIds (list): images to be downloaded
          :return:
          '''
          if tarDir is None:
              print('Please specify target directory')
              return -1
          if len(imgIds) == 0:
              imgs = self.imgs.values()
          else:
              imgs = self.loadImgs(imgIds)
          N = len(imgs)
          if not os.path.exists(tarDir):
              os.makedirs(tarDir)
          for i, img in enumerate(imgs):
              tic = time.time()
              fname = os.path.join(tarDir, img['file_name'])
              if not os.path.exists(fname):
                  urlretrieve(img['coco_url'], fname)
              print('downloaded {}/{} images (t={:0.1f}s)'.format(i, N, time.time()- tic))
docs: Download COCO images from mscoco.org server.
          :param tarDir (str): COCO results directory name
                 imgIds (list): images to be downloaded
          :return: