    yield intvl
            else:
                # logger.info(&#34;DEBUG: returning since we got {}&#34;.format(intvl))
                return

    def lasts(self):
        &#34;&#34;&#34;
        Yields all intervals which start at the last known start offset.
        &#34;&#34;&#34;
        laststart = None
        for intvl in reversed(self._by_start):
            if laststart is None:
                laststart = intvl[0]
                yield intvl
            elif intvl[0] == laststart:
             