 from forecast base time.</span>
<span class="sd">        Valid values are hours (HH) from forecast base time.</span>

<span class="sd">    Return</span>
<span class="sd">    ------</span>
<span class="sd">    step : list of str</span>
<span class="sd">        List of forecast steps in format e.g. [001, 002, ...]</span>
<span class="sd">    &#39;&#39;&#39;</span>
    <span class="kn">import</span> <span class="nn">numpy</span> <span class="k">as</span> <span class="nn">np</span>

    <span class="k">if</spa