Example of usage:

    FlexibleOneShotCrawler crawler = new FlexibleOneShotCrawler();
    SentencesCollector c = new SentencesCollector();
    c.setTarget("Learn"); // tells crawler which words he should looking for.
    ImagesCollector i = new ImagesCollector();

    crawler.configure()
            .initUrl("https://www.w3schools.com/") // tells crawler where he should start his work.
            .addCollector(c) 
            .addCollector(i);
			
    crawler.start();