Undefined Function Geoip_country_code_by_name() Fatal Error: Call To Undefined Function Issest() On Line 17 What Am I Doing Wrong?

Fatal error: Call to undefined function issest() on line 17 what am I doing wrong? - undefined function geoip_country_code_by_name()

I write a PHP code and get this error message because some onw know what I'm doing wrong Fatal error: Call to undefined function eatest () on line 17