Wordpress - Warning: call_user_func_array() expects parameter
<p>I'm learning how to make Setting API Options in WordPress but every time add a code into my functions.php file it brings up this error. </p>

<p>How do I fix this?  </p>

<pre><code>Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'my_plugin_menu' not found or invalid function name in /Applications/MAMP/htdocs/wp-test-sites/wp-includes/plugin.php on line 525 

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'my_plugin_menu' not found or invalid function name in /Applications/MAMP/htdocs/wp-test-sites/wp-includes/plugin.php on line 525 

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'my_plugin_menu' not found or invalid function name in /Applications/MAMP/htdocs/wp-test-sites/wp-includes/plugin.php on line 525 
</code></pre>