Fatal error Solution to Fatal error that occurs when writing PHP paging

Fatal error: Cannot redeclare htmtocode() (previously declared in D:www_localmytestconn.php:7) in D:www_localmytestconn.php on line 10
This error message appears when writing the paging file page.php
Google translates the meaning of this sentence It's "Fatal error: cannot redeclare htmtocode()"
The code on line 10 is

//Connect to the database
include("conn.php");
//Introduce the paging class File
include("page.class.php");
?>
After searching on the Internet, the possible reason is: two page program files are referenced and cause conflicts when they are loaded repeatedly in the memory.
Solution: Use include_once() instead of include

The above has introduced the solution to the fatal error that occurs when writing PHP paging, including the content of fatal errors. I hope it will be helpful to friends who are interested in PHP tutorials.