def from_cvat_tracks(cls, cvat_tracks):
        """Creates a :class:`CVATTaskLabels` instance that describes the active
        schema of the given annotations.

        Args:
            cvat_tracks: a list of :class:`CVATTrack` instances

        Returns:
            a :class:`CVATTaskLabels`
        """
        schema = etai.ImageLabelsSchema()
        for cvat_track in cvat_tracks:
            for anno in cvat_track.iter_annos():
                _label = anno.label
                schema.add_object_label(_label)

                if anno.outside is not None:
                    _attr = etad.BooleanAttribute("outside", anno.outside)
                    schema.add_object_attribute(_label, _attr)

                if anno.occluded is not None:
                    _attr = etad.BooleanAttribute("occluded", anno.occluded)
                    schema.add_object_attribute(_label, _attr)

                if anno.keyframe is not None:
                    _attr = etad.BooleanAttribute("keyframe", anno.keyframe)
                    schema.add_object_attribute(_label, _attr)

                for attr in anno.attributes:
                    _attr = attr.to_eta_attribute()
                    schema.add_object_attribute(_label, _attr)

        return cls.from_schema(schema)
Creates a :class:`CVATTaskLabels` instance that describes the active
        schema of the given annotations.

        Args:
            cvat_tracks: a list of :class:`CVATTrack` instances

        Returns:
            a :class:`CVATTaskLabels`
        
fiftyone/utils/cvat.py