class_docstr: A progress bar based on tqdm.
  
  This callback is one of the :func:`DEFAULT_CALLBACKS()`.
class_docstr_tok: ["A","progress","bar","based","on","tqdm",".","This","callback","is","one","of","the",":","func",":","`","DEFAULT_CALLBACKS","(",")","`","."]
code: def _after_train(self):
      if self._bar:  # training may get killed before the first step
          self._bar.close()
  
imports: import tqdm
  from six.moves import zip
  from ..compat import tfv1
  from ..tfutils.common import get_global_step_var, get_op_tensor_name
  from ..utils import logger
  from ..utils.naming import GLOBAL_STEP_INCR_OP_NAME
  from ..utils.utils import get_tqdm_kwargs
  from .base import Callback
label_desc: Use image node_id 8 for calling the ProgressBar obj's underlying member method code with example usage: obj._after_train() without return types