TYP: require _update_inplace gets Frame/Series, never BlockManager
ok shouldn't you change the doc-string / annotation of _update_inplace (and maybe add an assertion) to guarantee this? > and maybe add an assertion

Tricky since we could be dealing with a subclass.  I think its pretty clear in context. are remaining comments deal-breakers?  nice follow-ups to de-duplicate some code after this no my point on the _update_inplace method should only accept Series/Dataframe and not a BlockManager anymore 

i think that’s reasonable to add > no my point on the _update_inplace method should only accept Series/Dataframe and not a BlockManager anymore

Right, thats what this PR does.  The docstring is updated to reflect that.  Just havent added an annotation because we dont have a ready-made "same type as self" k fair enough

maybe an assertion would be good at some point