Add parens around unmarked clause

Add parens around unmarked clause

I'm not 100% sure what this sentence is saying, but I'm pretty sure it needs either commas or parentheses to break it up a little. I think parens make the most sense in this case assuming I am reading it correctly. Here's the original sentence and proposed edit in plaintext:

ORIG
 "...persistent objects which were removed from a collection or in some cases a scalar attribute may also be pulled into the Session of a parent object;..."

EDIT
 "...persistent objects which were removed from a collection (or in some cases a scalar attribute) may also be pulled into the Session of a parent object;..."