docs: def check_rev_options(self, rev, dest, rev_options):
          """Check the revision options before checkout to compensate that tags
          and branches may need origin/ as a prefix.
          Returns the SHA1 of the branch or tag if found.
          """
          revisions = self.get_tag_revs(dest)
          revisions.update(self.get_branch_revs(dest))
  
          origin_rev = 'origin/%s' % rev
          if origin_rev in revisions:
              # remote branch
              return [revisions[origin_rev]]
          elif rev in revisions:
              # a local tag or branch name
              return [revisions[rev]]
          else:
              logger.warn("Could not find a tag or branch '%s', assuming commit." % rev)
              return rev_options