public function build_attributes() {
		// setup attributes.
		$this->set_attributes();

		$attributes = [];
		foreach ( $this->attributes as $att => $value ) {
			if ( is_array( $value ) ) {
				$value = implode( ' ', $value );
			}
			$attributes[] = sprintf( '%s="%s"', esc_html( $att ), esc_attr( $value ) );
		}

		return implode( ' ', $attributes );
	}