title: How to run an existing function from Jupyter notebook
body: <p>I am using Jupyter notebook. In the same folder in which the notebook is running, I have a function f defined as </p>
  
  <pre><code> def f(x):
      return x**2
  </code></pre>
  
  <p>I have saved this function as f.py in the same folder. Now I want to call this function in the notebook that is running. How do I do that? If the function was typed into the notebook, I could have just typed</p>
  
  <pre><code>f(4)
  </code></pre>