How can I copy all contents (including folders) from folder A to the existing folder B with Python?
You can use the copytree function from the shutil package https://docs.python.org/3/library/shutil.html#shutil.copytree.
from shutil import copytree
src_path = "path/of/your/source/dir"
dest_path = "path/of/your/destination/dir"
copytree(src_path, dest_path, dirs_exist_ok=True)
The dirs_exist_ok=True
parameter is useful if the dest_path already exists, and you want to overwrite the existing files.