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Hello, I am try the plugin and I get this error

Warning: Missing argument 2 for WP_Widget::__construct(), called in /home/myweb/public_html/wp-includes/widgets.php on line 324 and defined in /home/yweb/public_html/wp-includes/widgets.php on line 93

thanks for support

http://ww.wp.xz.cn/extend/plugins/igreen-alexa-site-rank/