code: func (s *Storage) Create(rls *rspb.Release) error {
  	s.Log("creating release %q", makeKey(rls.Name, rls.Version))
  	if s.MaxHistory > 0 {
  		// Want to make space for one more release.
  		s.removeLeastRecent(rls.Name, s.MaxHistory-1)
  	}
  	return s.Driver.Create(makeKey(rls.Name, rls.Version), rls)
  }
docs: // Create creates a new storage entry holding the release. An
  // error is returned if the storage driver failed to store the
  // release, or a release with identical an key already exists.