tly, which may reveal the underlying
representation of a missing value (so be careful).</p><pre>f.raw(<span class="num">0</span>,<span class="num">0</span>) == <span class="num">1</span></pre><p><code>Frame</code> may be used in arithmetic expressions which operate on two <code>Frame</code>s or on a
<code>Frame</code> and a scalar value. In the former case, the two Frames will automatically
align along their indexes:</p><pre>f + f.shift(<span class="num">1</span>) == Frame(<span class="lit">'a'</span>-&gt;V