Is there a is_defined / is_set($var / $arr[‘key’] / $arr[‘key’][‘sub_key’] ) that returns TRUE if the variable is defined, NULL or not, that will not throw exceptions/errors if the array key is not set? Do they have an RFC for this?

I am new to Magento and I have noticed that everytime I run: bin/magento setup:install –base-url=http://localhost:8090 –backend-frontname=admin –db-host=magento_mysql –db-name=webshop –db-user=admin –db-password=test1234 –admin-firstname=admin […]