create_function is deprecated from php 7.2

create_function is deprecated from php 7.2, and this plugin should be updated. ??
https://www.php.net/manual/en/function.create-function.php

in file: /wp-charts/inc/charts-widget.php

around line 165.

Change this
add_action('widgets_init', create_function('', 'return register_widget("WP_Charts_Widget");'));

To this
add_action('widgets_init', function() { return register_widget("WP_Charts_Widget"); } );

OR use this for compatibility with older php versions.

 add_action('widgets_init', 'charts_widget_register_widget' );
 function charts_widget_register_widget() {
 	return register_widget("WP_Charts_Widget");
 }