def update(self, docs=None, split=0, parallelism=None, progress_bar=True):
        """Update the features of the specified candidates.

        :param docs: If provided, apply features to all the candidates in these
            documents.
        :param split: If docs is None, apply features to the candidates in this
            particular split.
        :type split: int
        :param parallelism: How many threads to use for extraction. This will
            override the parallelism value used to initialize the Featurizer if
            it is provided.
        :type parallelism: int
        :param progress_bar: Whether or not to display a progress bar. The
            progress bar is measured per document.
        :type progress_bar: bool
        """
        self.apply(
            docs=docs,
            split=split,
            train=True,
            clear=False,
            parallelism=parallelism,
            progress_bar=progress_bar,
        )
Update the features of the specified candidates.

        :param docs: If provided, apply features to all the candidates in these
            documents.
        :param split: If docs is None, apply features to the candidates in this
            particular split.
        :type split: int
        :param parallelism: How many threads to use for extraction. This will
            override the parallelism value used to initialize the Featurizer if
            it is provided.
        :type parallelism: int
        :param progress_bar: Whether or not to display a progress bar. The
            progress bar is measured per document.
        :type progress_bar: bool