<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def clean():
 """Clean up previous garbage"""

    os.chdir(os.path.join(project_root, 'docs'))
    sh("make clean")
    os.chdir(project_root)
    sh("rm -rf pyoauth2.egg-info")