or +</a></li>
      <li><a href="dart-core/Duration/operator_minus.html">operator -</a></li>
      <li><a href="dart-core/Duration/operator_less.html">operator <</a></li>
      <li><a href="dart-core/Duration/operator_less_equal.html">operator <=</a></li>
      <li><a href="dart-core/Duration/operator_equals.html">operator ==</a></li>
      <li><a href="dart-core/Duration/operator_greater.html">operator ></a></li>
      <li><a href="dart-core/Duration/operator_greater_equal.html">operator >=</a></li>
      