public static List<IoRegistry> createRegistries(final Configuration configuration) {
        if (configuration.containsKey(IoRegistry.IO_REGISTRY)) {
            final Object property = configuration.getProperty(IoRegistry.IO_REGISTRY);
            if (property instanceof IoRegistry)
                return Collections.singletonList((IoRegistry) property);
            else if (property instanceof List)
                return createRegistries((List) property);
            else if (property instanceof String)
                return createRegistries(Arrays.asList(((String) property).split(",")));
            else
                throw new IllegalArgumentException("The provided registry object can not be resolved to an instance: " + property);
        } else
            return Collections.emptyList();
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/io/util/IoRegistryHelper.java