protected function prepare_config( $arr ) {
		$result = [];

		if ( ! is_array( $arr ) ) {
			return $result;
		}

		$arr = array_merge( $this->get_default_config(), $arr );

		foreach ( $arr as $key => $value ) {
			$res          = $this->config( $key );
			$result[$key] = is_null( $res ) ? $value : $res;
		}

		return apply_filters( 'digster/config', $result );
	}