Warning: call_user_func_array() | WordPress.org

Hello there, I did put a code in my function.php to install Google GTM. Here is the code

function gtm_head(){
  ?>
    <!-- Google Tag Manager -->
<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l="+l:"';j.async=true;j.src="https://www.googletagmanager.com/gtm.js?id="+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','GTM-XXXXXX');</script>
<!-- End Google Tag Manager -->
    <!-- End Google Tag Manager -->
  <?php
}
add_action( 'wp_head', 'gtm_head', 1 );

/**
 * Google Tag Manager script in <body> 
 */
function gtm_body_open(){
  ?>
  <!-- Google Tag Manager (noscript) -->
	<noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-XXXXXXX"
	height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
	<!-- End Google Tag Manager (noscript) -->
  <?php
}
add_action( 'wp_body_open', ' gtm_body_open', 1 );

But now there’s a line of error on my front website : Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘ gtm_body_open’ not found or invalid function name in /home/u161678441/domains/michaeldri.com/public_html/blog/wp-includes/class-wp-hook.php on line 308

I looked in the class-wp-hook file but I don’t know what to do…. Since i’m not a pro in development… Here the section of code in the file :

// Avoid the array_slice() if possible.
				if ( 0 == $the_['accepted_args'] ) {
					$value = call_user_func( $the_['function'] );
				} elseif ( $the_['accepted_args'] >= $num_args ) {
					$value = call_user_func_array( $the_['function'], $args );
				} else {
					$value = call_user_func_array( $the_['function'], array_slice( $args, 0, (int) $the_['accepted_args'] ) );
				}
			}
		} while ( false !== next( $this->iterations[ $nesting_level ] ) );

		unset( $this->iterations[ $nesting_level ] );
		unset( $this->current_priority[ $nesting_level ] );

		$this->nesting_level--;

		return $value;
	}

Please can you tell me what to do with that ? 🙁 🙁 🙁

What should I add ?

I would be really thankful !!!

The page I need help with: [log in to see the link]

 

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