Fatal error: Uncaught TypeError: array_key_exists(): Argument #2 ($array) must be of type array, null given in /home/datadir/applications/econome-dev/API/V2_explore/exp_measure_variant/POST-variants.php:8 Stack trace: #0 {main} thrown in /home/datadir/applications/econome-dev/API/V2_explore/exp_measure_variant/POST-variants.php on line 8