@property<EOL><INDENT>def n_subdir(self):<DEDENT>
self.assert_is_dir_and_exists()<EOL>n = <NUM_LIT:0><EOL>for _ in self.select_dir(recursive=False):<EOL><INDENT>n += <NUM_LIT:1><EOL><DEDENT>return n<EOL>
Count how many folders in this directory (doesn't include folder in
sub folders).