docs: public Collection<EsaResource> getMatchingEsas(final FilterableAttribute attribute, final String identifier) throws RepositoryBackendException {
          Collection<EsaResource> resources = cycleThroughRepositories(new RepositoryInvoker<EsaResource>() {
              @Override
              public Collection<EsaResource> performActionOnRepository(RepositoryConnection connection) throws RepositoryBackendException {
                  return connection.getMatchingEsas(attribute, identifier);
              }
          });
          return resources;
      }