class_docstr: Extension that makes a symbolic link to the best model
  
  :param str key: Key of value
  :param str prefix: Prefix of model files and link target
  :param str suffix: Suffix of link target
class_docstr_tok: ["Extension","that","makes","a","symbolic","link","to","the","best","model",":","param","str","key",":","Key","of","value",":","param","str","prefix",":","Prefix","of","model","files","and","link","target",":","param","str","suffix",":","Suffix","of","link","target"]
code: def __init__(self, key, prefix="model", suffix="best"):
      super(MakeSymlinkToBestModel, self).__init__()
      self.best_model = -1
      self.min_loss = 0.0
      self.key = key
      self.prefix = prefix
      self.suffix = suffix
  
imports: import logging
  import os
  import random
  import chainer
  import h5py
  import numpy
  from chainer.training import extension
  from tqdm import tqdm
label_desc: Use image node_id 1 to create a new MakeSymlinkToBestModel object from inherited base classes: extension with example: obj = MakeSymlinkToBestModel(key, prefix, suffix)