• I have visited the [source website], and in particular
  read the [known issues]
• I have searched through the [issue tracker] for duplicates
• I have mentioned version numbers, operating system and
  environment, where applicable:

import tqdm, sys
print(tqdm.__version__, sys.version, sys.platform)
4.28.1 3.7.1 | packaged by conda-forge | (default, Nov 13 2018, 09:50:42) 
[Clang 9.0.0 (clang-900.0.37)] darwin

Using from tqdm import tqdm_notebook and the following code:

for i in tqdm_notebook(range(6, 13)):
    do_stuff(i)

I get:

HBox(children=(IntProgress(value=0, max=7), HTML(value='')))

as output instead of a progress bar.