Question about implementing Singletons

Just came upon programming patterns and learned about singleton. I’m on the process of creating my first game and it contains several managers (see attached).I wanted to implement singleton on each of the managers,but the only way I can think is copy pasting the singleton pattern on each awake method script attached to each manager. Question would be, is there a more efficient way to do it rather than pasting the pattern on each awake method?

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