_type</a>&#160;</td>
          <td class="paramname"><em>v</em>&#160;</td>
        </tr>
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          <td></td>
          <td>)</td>
          <td></td><td> const</td>
        </tr>
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  </td>
  <td class="mlabels-right">
<span class="mlabels"><span class="mlabel">pure virtual</span></span>  </td>
  </tr>
</table>
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<p>Get specific value for period <em>p</em> according to a value_type <em>v</em> </p>

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