text: Title: Add normalisation options
  Body: Hi! 
  
  First, thanks for this library which is really awesome! 
  
  I have this dataset where I'm analyzing Premie league football since 1992. I want to plot a Ridge plot with each subplot being Yellow_card, red_card, goal, penalty, etc, and see the distribution over a 90mn period to see when these actions happen the most. Of course, there is way more yellow cards than goals and way more goals that red card which results in a plot like this:
  
  <img src="https://i.ibb.co/SVCwQrG/Screenshot-2021-07-13-at-01-29-37.png" alt="Screenshot-2021-07-13-at-01-29-37" border="0">
  
  Is there a way to see everything, I check the parameters and the code but I'm not that good in python to understand everything yet...
  
  Any help?