'Return the size of the directory given by path
path: <string>'

def __folder_size(self, path):

    ret = 0
    for f in scandir(path):
        if (f.is_dir() and ((f.name != '.') or (f.name != '..'))):
            ret += self.__folder_size(os.path.join(path, f.name))
        else:
            try:
                ret += f.stat().st_size
            except OSError:
                pass
    return ret
