How to hide code Jupyter Notebook

[Larz60+]

Hi,

In Jupyter Notebook you can embed a web video with a code cell like:

from IPython.display import HTML

HTML('<iframe width="560" height="315" src="https://www.youtube.com/embed/nKW8Ndu7Mjw?rel=0&amp;controls=0&amp;showinfo=0" frameborder="0" allowfullscreen></iframe>')

However, when that is run you get the following, which is ugly:
   

I found what was supposed to be a solution, by adding a comment on first line:

# @hidden_cell

But it doesn't appear to work.
Does anyone know what works. I want to see the video, but not the code.