pressable/mixpanel-wordpress — pull request #1 by xben (2014-11-17 09:54:29+00:00)
Title: add missing static function declaration

Refactor to Strict standards
Otherwise you could get this message with newer php versions:
( ! ) Strict standards: call_user_func_array() expects parameter 1 to be a valid callback, non-static method MixPanel::insert_event() should not be called statically in ...