public <E extends Enum<E>> E getEnum(List<String> keyAliases, E defaultValue, Function<String, E> converter) {
        return getEnum(keyAliases, defaultValue, defaultValue.getDeclaringClass(), converter);
    }
Parse an enum from the options using the key aliases.

@param keyAliases the key aliases
@param defaultValue the default value
@param converter a converter function to transform from String to Enum
@param <E> target enum type
@return the parsed enum, or the default value if none provided.
common/config/src/main/java/io/apiman/common/config/options/GenericOptionsParser.java