text: Title: Retrieve data added with a folium Draw plugin
  Body: Hello,
  
  This is not an issue but a question.
  I didn't found a better place to ask...
  
  I use a folium.plugins.Draw and I would like to get the objects interactively added on the map (rectangles for example)
  Something like "Draw.drawnItems" but folium says : "'Draw' object has no attribute 'drawnItems'" and I didn't found any code example 
  
  Could you help me ?
  
  