luisToLuContent = function(luisJSON){
    let fileContent = '';
    let luisObj = new helperClasses.rLuisObj();
    (luisJSON.intents || []).forEach(function(intent) {
        luisObj.intents.push(new helperClasses.intent(intent, []));
    });
    // add utterances to luisObj
    updateUtterancesList(luisJSON.utterances, luisObj.intents, 'text');
    // add patterns to luisObj
    updateUtterancesList(luisJSON.patterns, luisObj.intents, 'pattern');

    // Parse Intents
    fileContent += parseIntentsToLu(luisObj, luisJSON)
    fileContent += parseEntitiesToLu(luisJSON)
    fileContent += parseToLuPrebuiltEntities(luisJSON)
    fileContent += handlePhraseLists(luisJSON.model_features);
    fileContent += handlePhraseLists(luisJSON.phraselists);
    fileContent += parseToLuClosedLists(luisJSON)
    fileContent += parseRegExEntitiesToLu(luisJSON.regex_entities)
    // handle regexEntities in json returned from luis export api
    // similar with regex_entities
    fileContent += parseRegExEntitiesToLu(luisJSON.regexEntities)
    fileContent += parseCompositesToLu(luisJSON)
    fileContent += parsePatternAnyEntitiesToLu(luisJSON)
    return fileContent
}
Parses a Luis object into Lu Content
@param {Luis} luisJSON
@returns {string} Lu Content
@throws {exception} Throws on errors. exception object includes errCode and text.