r creating a new annotation are ignored.
            type: the type of a new annotation to create
            annset: if not None, create the new annotation in this set instead of the one used for matching
            features: the features of a new annotation to create. This can be a GetFeatures helper for copying
                the features from another annotation in the results
            span: the span of the annotation, this can be a GetSpan helper for copying the span from another
                an