title: What does `exit` keyword do in Python3 with Jupyter Notebook?
body: <p>I am currently using Python3 in Jupyter Notebook and I just ran into a keyword <code>exit</code>. What does this keyword do ?</p>
  
  <pre><code>with open("some_file.txt") as f:
      for lines in f:
          print(lines)
          exit
  </code></pre>