is the same as the given class will be retrieved.</dd>
<dd><code>owner</code> - Optional owner of last operation to retrieve.  If null, the last
                  operation regardless of owner will be retrieved; if non-null, the last operation
                  matching the given owner will be retrieved.</dd>
<dd><code>mergeMode</code> - May be either <a href="#MERGE_MODE_NONE"><code>MERGE_MODE_NONE</code></a>, <a href="#MERGE_MODE_UNIQUE"><code>MERGE_MODE_UNIQUE</code></a>,
                  or <a href="#M