I have been trying to integrate the Experiments feature into our site. I have set up a new experiment at https://app.posthog.com/experiments and it is running.

I am currently using "posthog/posthog-php": "^3.0" and php 8.1.
I have been trying to get PostHog::getFeatureFlag('sell-your-classic-test', 'some distinct id'); to work but it would keep returning null. I tried:
if (PostHog::isFeatureEnabled('sell-your-classic-test', 'some distinct id')) {
// do something here
}
But this always returns false. I then read about Local Evaluation which requires a personal API key. I created one and have added it to PostHog::init but when I do this I get the below error:
array_key_exists(): Argument #2 ($array) must be of type array, null given
Which is found in vendor/posthog/posthog-php/lib/Client.php:356.

This is the code that I'm running:
PostHog::init(
apiKey: "phc_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
personalAPIKey: "phx_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
);
I have also tried:
PostHog::init(
"phc_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
[],
null,
"phx_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
);
Any help would be helpful.
I have been trying to integrate the Experiments feature into our site. I have set up a new experiment at https://app.posthog.com/experiments and it is running.

I am currently using
"posthog/posthog-php": "^3.0"and php8.1.I have been trying to get
PostHog::getFeatureFlag('sell-your-classic-test', 'some distinct id');to work but it would keep returningnull. I tried:But this always returns false. I then read about Local Evaluation which requires a personal API key. I created one and have added it to
PostHog::initbut when I do this I get the below error:Which is found in

vendor/posthog/posthog-php/lib/Client.php:356.This is the code that I'm running:
I have also tried:
Any help would be helpful.