I am trying to execute a command inside a Python script:

```
import subprocess
output_process = 
   subprocess.Popen("javac -cp C:\Users\MyUsername\Desktop\htmlcleaner-2.2.jar Scrapping_lastfm.java",
                    shell=True, stdout=subprocess.PIPE)

```

But I am getting an error `package org.htmlcleaner does not exist`.

If I run the javac command independently, it executes fine..

My current working directry is `C:\Users\MyUsername`.