( $content, '<!--nextpage-->' ) ) {
			$content = str_replace( "\n<!--nextpage-->\n", '<!--nextpage-->', $content );
			$content = str_replace( "\n<!--nextpage-->", '<!--nextpage-->', $content );
			$content = str_replace( "<!--nextpage-->\n", '<!--nextpage-->', $content );

			// Remove the nextpage block delimiters, to avoid invalid block structures in the split content.
			$content = str_replace( '<!-- wp:nextpage -->', '', $content );
			$content = str_replace( '<!-- /wp:nextpage -->', '', $content );

			// Ignore nextpage at the beginning of the content.
			if ( str_starts_with( $content, '<!--nextpage-->' ) ) {
				$content = substr( $content, 15 );
			}

			$pages = explode( '<!--nextpage-->', $content );
		} else {
			$pages = array( $post->post_content );
		}

		/**
		 * Filters the "pages" derived from splitting the post content.
		 *
		 * "Pages" are determined by splitting the post content based on the presence
		 * of `<!-- nextpage -->` tags.
		 *
		 * @since 4.4.0
		 *
		 * @param string[] $pages Array of "pages" from the post content split by `<!-- nextpage -->` tags.
		 * @param WP_Post  $post  Current post object.
		 */
		$pages = apply_filters( 'content_pagination', $pages, $post );

		$numpages = count( $pages );

		if ( $numpages > 1 ) {
			if ( $page > 1 ) {
				$more = 1;
			}
			$multipage = 1;
		} else {
			$multipage = 0;
		}

		$elements = compact( 'id', 'authordata', 'currentday', 'currentmonth', 'page', 'pages', 'multipage', 'more', 'numpages' );

		return $elements;
	}

	/**
	 * Generates cache key.
	 *
	 * @since 6.1.0
	 *
	 * @global wpdb $wpdb WordPress database abstraction object.
	 *
	 * @param array  $args Query arguments.
	 * @param string $sql  SQL statement.
	 * @return string Cache key.
	 */
	protected function generate_cache_key( array $args, $sql ) {
		global $wpdb;

		unset(
			$args['cache_results'],
			$args['fields'],
			$args['lazy_load_term_meta'],
			$args['update_post_meta_cache'],
			$args['update_post_term_cache'],
			$args['update_menu_item_cache'],
			$args['suppress_filters']
		);

		$placeholder = $wpdb->placeholder_escape();
		array_walk_recursive(
			$args,
			/*
			 * Replace wpdb placeholders with the string used in the database
			 * query to avoid unreachable cache keys. This is necessary because
			 * the placeholder is randomly generated in each request.
			 *
			 * $value is passed by reference to allow it to be modified.
			 * array_walk_recursive() does not return an array.
			 */
			static function ( &$value ) use ( $wpdb, $placeholder ) {
				if ( is_string( $value ) && str_contains( $value, $placeholder ) ) {
					$value = $wpdb->remove_placeholder_escape( $value );
				}
			}
		);

		// Replace wpdb placeholder in the SQL statement used by the cache key.
		$sql = $wpdb->remove_placeholder_escape( $sql );
		$key = md5( serialize( $args ) . $sql );

		$last_changed = wp_cache_get_last_changed( 'posts' );
		if ( ! empty( $this->tax_query->queries ) ) {
			$last_changed .= wp_cache_get_last_changed( 'terms' );
		}

		return "wp_query:$key:$last_changed";
	}

	/**
	 * After looping through a nested query, this function
	 * restores the $post global to the current post in this query.
	 *
	 * @since 3.7.0
	 *
	 * @global WP_Post $post Global post object.
	 */
	public function reset_postdata() {
		if ( ! empty( $this->post ) ) {
			$GLOBALS['post'] = $this->post;
			$this->setup_postdata( $this->post );
		}
	}

	/**
	 * Lazyloads term meta for posts in the loop.
	 *
	 * @since 4.4.0
	 * @deprecated 4.5.0 See wp_queue_posts_for_term_meta_lazyload().
	 *
	 * @param mixed $check
	 * @param int   $term_id
	 * @return mixed
	 */
	public function lazyload_term_meta( $check, $term_id ) {
		_deprecated_function( __METHOD__, '4.5.0' );
		return $check;
	}

	/**
	 * Lazyloads comment meta for comments in the loop.
	 *
	 * @since 4.4.0
	 * @deprecated 4.5.0 See wp_lazyload_comment_meta().
	 *
	 * @param mixed $check
	 * @param int   $comment_id
	 * @return mixed
	 */
	public function lazyload_comment_meta( $check, $comment_id ) {
		_deprecated_function( __METHOD__, '4.5.0' );
		return $check;
	}
}
<br />
<b>Fatal error</b>:  require(): Failed opening required '/home/healths/public_html/wp-includes/theme.php' (include_path='.:') in <b>/home/healths/public_html/wp-settings.php</b> on line <b>172</b><br />
<br />
<b>Fatal error</b>:  Uncaught Error: Call to a member function set() on null in /home/healths/public_html/wp-includes/l10n.php:806
Stack trace:
#0 /home/healths/public_html/wp-includes/l10n.php(900): load_textdomain()
#1 /home/healths/public_html/wp-includes/class-wp-fatal-error-handler.php(47): load_default_textdomain()
#2 [internal function]: WP_Fatal_Error_Handler-&gt;handle()
#3 {main}
  thrown in <b>/home/healths/public_html/wp-includes/l10n.php</b> on line <b>806</b><br />