@staticmethod
def _split_overlapping(variant_pairs, anchor, which='both'):
    """
        Split the variants hitting the anchor into two
        """
    for ref, alt in variant_pairs:
        if ref.start < anchor < ref.end:
            mid = anchor - ref.start
            if which == 'left' or which == 'both':
                yield ref[:mid], alt[:mid]
            if which == 'right' or which == 'both':
                yield ref[mid:], alt[mid:]
        else:
            yield ref, alt
