All labels present in the match patterns.

        RETURNS (set): The string labels.

        DOCS: https://spacy.io/api/entityruler#labels

def labels(self):
        """All labels present in the match patterns.

        RETURNS (set): The string labels.

        DOCS: https://spacy.io/api/entityruler#labels
        """
        all_labels = set(self.token_patterns.keys())
        all_labels.update(self.phrase_patterns.keys())
        return tuple(all_labels)