https://github.com/scikit-learn/scikit-learn/blob/74ae6a0aa06e14f15039786d18ac56be92c14594/sklearn/metrics/cluster/supervised.py#L751 entropy must be inputed with frequency table of `labels_true` / `labels_pred`, not those array directly. Example solution ``` from collections import Counter freq_table = [x[1] for x in dict(Counter(labels_true)).items()] entropy(freq_table) ```