 class="p">(</span><span class="s">'</span><span class="se">\n</span><span class="s">'</span> <span class="o">+</span> <span class="n">witness_vote</span> <span class="o">+</span> <span class="s">' cannot be voted for more than once'</span><span class="p">)</span>
        <span class="nb">exit</span><span class="p">()</span>
    <span class="n">client</span><span class="o">.</span><span class="n">approve_witness</span><span class="p">(</span><span class="n">witness</span><span class="o">=</span><span class=