A Jupyter header to convert the following code into a .py file.

put_this_in_ipynb_top.py

import __main__ as main
if not hasattr(main, '__file__'):
    jupyter_name = 'your-jupyter-filename'

    import os
    import subprocess
    subprocess.call(['jupyter',
                     'nbconvert',
                     '--to',
                     'script',
                     jupyter_name+'.ipynb'])
    
    pytxt = open(jupyter_name+'.py').read()
    with open(jupyter_name+'.py', 'w') as f:
        strt = False
        outtxt = []
        for line in pytxt.split('\n'):
            if '### start py ###'.replace(' ','') in line:
                strt = True
                continue
                
            if not strt: continue
            if line.startswith('# In['): continue
            if line.startswith('# Out['): continue
                
            outtxt.append(line)
        f.write('\n'.join(outtxt))