def append(self, feature, label=None):
        """
        Add a (feature, label) entry into the dataset.
        A None label indicates an unlabeled entry.

        Parameters
        ----------
        feature : {array-like}, shape = (n_features)
            Feature of the sample to append to dataset.

        label : {int, None}
            Label of the sample to append to dataset. None if unlabeled.

        Returns
        -------
        entry_id : {int}
            entry_id for the appened sample.
        """
        self.data.append((feature, label))
        self.modified = True
        return len(self.data) - 1
dataset/ETHPy150Open ntucllab/libact/libact/base/dataset.py/Dataset.append/original