title: how to make a nested tqdm bars on jupyter notebook
body: <p>Here is an example for nested tqdm bar</p>
  
  <pre><code>import time
  import tqdm
  for i in tqdm.tqdm(range(3)):
      for j in tqdm.tqdm(range(5)):
          print(i," : ", j)
  </code></pre>
  
  <p>I try it on jupyter notebook but it does not show any thing without error! However, it works coorectly on ipython console!</p>