ll intervals which start at the smallest known offset.</p></div>
<details class="source">
<summary>
<span>Expand source code</span>
</summary>
<pre><code class="python">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 laststa