I am playing around with Jupyter notebook and I notice that in my most recent version of Scalation (downloaded some time late last month), it does not support scalation.relalgebra. So when I import scalation.relalgebra.Relation it says it can't find relalgebra in scalation. I found that the method Relation is in the library columnar_db now. So when I do import scalation.columnar_db.Relation. It is all good!
I believe other notebooks have similar issues too on relalgebra library