code: func (ts *Store) Check(id string) (string, error) {
  	treeStoreKeyLock, err := lock.SharedKeyLock(ts.lockDir, id)
  	if err != nil {
  		return "", errwrap.Wrap(errors.New("error locking tree store"), err)
  	}
  	defer treeStoreKeyLock.Close()
  
  	return ts.check(id)
  }
docs: // Check verifies the treestore consistency for the specified id.