I am getting this error in single page with comment.

‘twentyten_comment’ is a function in functions.php of Twenty Ten;

have you done any edits

in functions.php
(from line 300) starts with:
function twentyten_comment( $comment, $args, $depth ) {

or in comments.php, where this callback function is referenced?
this is the line in coments.php:

wp_list_comments( array( 'callback' => 'twentyten_comment' ) );

Yes i am trying to make a new templates of my own.i have edited both the files ho can i solve this problem.

I’m having the same problem with a wordpress site I inherited from another developer. I’ve bookmarked this thread in the hope you find a solution.

@rddcse

can you paste the code of these two files into a https://wordpress.pastebin.com/ each and post these two links here.

in the meantime:
edit this line from comments.php:
wp_list_comments( array( 'callback' => 'twentyten_comment' ) );
and change ‘tentyten_comment’ to the function name of an existing ‘comments’ function; i.e. the name of the comments function you are working on at the moment in functions.php of the theme.

or bring it back to the ’empty’ state:
wp_list_comments();
which should remove the error message.