 id="arg-x">x<a class="anchor" aria-label="anchor" href="#arg-x"></a></dt>
<dd><p>character, valid pitch notation, e.g., <code>"a2"</code> or <code>"a,"</code>.</p></dd>


<dt id="arg-y">y<a class="anchor" aria-label="anchor" href="#arg-y"></a></dt>
<dd><p>character, same as <code>x</code> for the sequence <code>x:y</code>. If a number, the
length of the sequence from <code>x</code> and the sign of <code>y</code> determines the direction.</p></dd>


<dt id="arg-key">key<a class="anchor" aria-label="anchor" 