title: What is the usage of tag over the cell in jupyter?
body: <p>I found that, in jupyter notebook, there is a tag tool over the cell, which can be activated by "View - Cell Toolbar - Tags". But I can not figure out, why we need these tags. Can someone give some suggestions or usage examples? </p>
  
  <p><a href="https://i.stack.imgur.com/l495J.png" rel="noreferrer"><img src="https://i.stack.imgur.com/l495J.png" alt="enter image description here"></a></p>