Undefined variable: lang_attribute …

Hi,
i recently installed your plugin..but i got this error.

There’s a way to fix it ?

Thank you

Notice: Undefined variable: lang_attribute in /plugins/google-language-translator/google-language-translator.php on line 385
Notice: Undefined variable: english_flag_choice in /plugins/google-language-translator/google-language-translator.php on line 372
Notice: Undefined variable: english_flag_choice in /plugins/google-language-translator/google-language-translator.php on line 375
Notice: Undefined variable: lang_attribute in /plugins/google-language-translator/google-language-translator.php on line 385
Notice: Undefined variable: lang_attribute in /plugins/google-language-translator/google-language-translator.php on line 385 

... & more..!

https://ww.wp.xz.cn/plugins/google-language-translator/