This is inspired from the original best answer provided by atzz, I just added replace file / folder logic. So it doesn't actually merge, but deletes the existing file/ folder and copies the new one:
import shutil
import os
def copytree(src, dst, symlinks=False, ignore=None):
for item in os.listdir(src):
s = os.path.join(src, item)
d = os.path.join(dst, item)
if os.path.exists(d):
try:
shutil.rmtree(d)
except Exception as e:
print e
os.unlink(d)
if os.path.isdir(s):
shutil.copytree(s, d, symlinks, ignore)
else:
shutil.copy2(s, d)
#shutil.rmtree(src)
Uncomment the rmtree to make it a move function.