                   # if the interval starts
                    if intvl[1] &gt; start:
                        yield intvl

    def firsts(self):
        &#34;&#34;&#34;
        Yields all intervals which start at the smallest known offset.
        &#34;&#34;&#34;
        laststart = None
        # logger.info(&#34;DEBUG: set laststart to None&#34;)
        for intvl in self._by_start.irange_key():
            # logger.info(&#34;DEBUG: checking interval {}&#34;.format(intvl))
            if laststart is No