How do I remove/delete a folder that is not empty?

import shutil
shutil.rmtree(dest, ignore_errors=True)

From the python docs on os.walk():

# Delete everything reachable from the directory named in 'top',
# assuming there are no symbolic links.
# CAUTION:  This is dangerous!  For example, if top == '/', it
# could delete all your disk files.
import os
for root, dirs, files in os.walk(top, topdown=False):
    for name in files:
        os.remove(os.path.join(root, name))
    for name in dirs:
        os.rmdir(os.path.join(root, name))

import shutil

shutil.rmtree('/folder_name')

Standard Library Reference: shutil.rmtree.

By design, rmtree fails on folder trees containing read-only files. If you want the folder to be deleted regardless of whether it contains read-only files, then use

shutil.rmtree('/folder_name', ignore_errors=True)

from python 3.4 you may use :

import pathlib

def delete_folder(pth) :
    for sub in pth.iterdir() :
        if sub.is_dir() :
            delete_folder(sub)
        else :
            sub.unlink()
    pth.rmdir() # if you just want to delete the dir content but not the dir itself, remove this line

where pth is a pathlib.Path instance. Nice, but may not be the fastest.