s <span class="emphasis"><em><span class="bold"><strong>reverse insertion (1)</strong></span></em></span>
          is different from <span class="bold"><strong>stl's</strong></span> erase semantics,
          because value pairs are deleted only, if key <span class="emphasis"><em><span class="bold"><strong>and</strong></span></em></span>
          data values are found. Only <span class="emphasis"><em><span class="bold"><strong>erasure by
          key objects (2)</strong></span></em></span> works like the