code: func (impl *repoImpl) GetPrefixMetadata(c context.Context, r *api.PrefixRequest) (resp *api.PrefixMetadata, err error) {
  	// It is fine to implement this in terms of GetInheritedPrefixMetadata, since
  	// we need to fetch all inherited metadata anyway to check ACLs.
  	inherited, err := impl.GetInheritedPrefixMetadata(c, r)
  	if err != nil {
  		return nil, err
  	}
  	// Have the metadata for the requested prefix? It should be the last if so.
  	if m := inherited.PerPrefixMetadata; len(m) != 0 && m[len(m)-1].Prefix == r.Prefix {
  		return m[len(m)-1], nil
  	}
  	// Note that GetInheritedPrefixMetadata checked that the caller has permission
  	// to view the requested prefix (via some parent prefix ACL), so sincerely
  	// reply with NotFound.
  	return nil, noMetadataErr(r.Prefix)
  }
docs: ////////////////////////////////////////////////////////////////////////////////
  // Prefix metadata RPC methods + related helpers including ACL checks.
  // GetPrefixMetadata implements the corresponding RPC method, see the proto doc.