function has_shortcode( $content, $tag ) {
		if ( false === strpos( $content, '[' ) ) {
			return false;
		}

		if ( shortcode_exists( $tag ) ) {
			preg_match_all( '/' . get_shortcode_regex() . '/s', $content, $matches, PREG_SET_ORDER );
			if ( empty( $matches ) ) {
				return false;
			}

			foreach ( $matches as $shortcode ) {
				if ( $tag === $shortcode[2] ) {
					return true;
				} elseif ( ! empty( $shortcode[5] ) && has_shortcode( $shortcode[5], $tag ) ) {
					return true;
				}
			}
		}

		return false;
	}