Adding magnitude to holiday effects

I'm not sure if there is a ticket or not as I couldn't find one related to my problem. I understand that when you create the holiday dataframe to feed into the Prophet instantiation the model interprets it as a binary variable. Is there a way to add magnitude to the binary column? I have custom events which have volumes associated with it which i want to factor it in instead of adding them as regressors manually. If I added the magnitude component in the model how is it interpreted in the model?