如何在单个变量中存储多个语句？

Question

I want to output my testing keys using just one variable for simplicity. How would I do this? Below is my attempt, which doesn't seem to work.

$Braintree_Keys = (

    Braintree_Configuration::environment('test');
    Braintree_Configuration::merchantId('A');
    Braintree_Configuration::publicKey('B');
    Braintree_Configuration::privateKey('C');

    );