A new open-source module called cleanlab.multiannotator has been developed for measuring the quality of multi-annotator classification data using novel CROWDLAB algorithms. The module can estimate consensus labels, quality scores for each consensus label and annotator, and is more effective than existing solutions on real-world data. It works by forming a probabilistic ensemble prediction considering the labels assigned by each annotator as outputs from other predictors. This approach allows CROWDLAB to still perform effectively even when the classifier is suboptimal or a few of the annotators often give incorrect labels.