Have you ever thought "Hmm I like this lighting setup but it's all a bit dim / too bright.." You can change the exposure values of Maya default and Arnold lights by a relative ammount so that every light's exposure gets increased/decreased by the same ammount.

By default this option ignores hidden/disabled lights

• Override: Absolute change -> sets all exposures to given a amount, disregarding current values
• Selected lights only -> Only effect selected lights
• Include hidden lights -> Effect hidden/disabled lights as well

You can drag and drop the .py file either:

• into the script editor and run it that way
• or from the script editor (while having it all selected) onto the toolbar to save it there for later use

• If you'd like to just set absolute values for multiple lights, there's already a built in function for it in the Arnold -> Utilities -> Light editor menu
• This project was mainly just a learning experience, but it might be updated to work with different renderengines used with Maya