title: Run edited python script step by step / without reloading dataset
body: <p>I work on a python script executing standard image recognition processing using tensorflow. Using Python 3.8, Tensorflow 2, Idle lauched from a virtual env.</p>
  <p>Since I am following a tutorial, I would like to augment and execute my script chunk by chunk : e.g.</p>
  <ul>
  <li>write the code for the data load</li>
  <li>execute</li>
  <li>write the code for training</li>
  <li>execute only training (without reloading the data)</li>
  </ul>
  <p>Is there a way to run a python script chunk by chunk, without restarting the idle shell, and keeping results from the previous steps?</p>