ass="m-doc-wrap">) const -&gt; const Value&amp;</span>
            </dt>
            <dd>Returns the value to modify.</dd>
            <dt id="a8bb164a991f6cd84ab96f1a017b0c265">
              <span class="m-doc-wrap-bumper">auto <a href="#a8bb164a991f6cd84ab96f1a017b0c265" class="m-doc-self">delta_property</a>(</span><span class="m-doc-wrap">) const -&gt; const Property&amp;</span>
            </dt>
            <dd>Returns how much to add to the property when the action is updated the given number of times