n duration.</span>
<span class="sd">    - **shift_backward(delta=None)**: Shifts the time range backward by a specified delta or its own duration.</span>
<span class="sd">    - **extend_range(start_delta, end_delta)**: Extends the start and end times of the time range by the specified deltas.</span>
<span class="sd">    &quot;&quot;&quot;</span>
    <span class="k">def</span> <span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">a</span>