How to call a static function at game start

Hello Unity Answers and thankyou, I'm new to Unity and loving it so far. I'm setting up basic game tools and functions I've used in previous code, and for things like Dictionary initialization I would want to call a static function for it when the game initializes, not when each scene starts. Is this possible in Unity? I know Unity is structured very differently to the traditional Main() loop and so on, and I should work with scenes and empty game objects, but for this kind of limited thing, it'd be better to make the call only once. Thanks Matt the Pie