Get range of commits

[Tymon13]

Hello,

I was trying to run commits(ref="6813170..b0974a5"), same as I'd run git log, but apperently it's not working in git2r.

Error message:

Error in lookup_commit(.Call(git2r_reference_dwim, repo, ref)) : 
  Error in 'git2r_reference_dwim': could not use '6813170..b0974a5' as valid reference name

Is it possible to add this functionality?