</span>
    <span class="n">expiry_month</span><span class="p">:</span> <span class="nb">str</span>

    <span class="c1">#: 4-digit expiry year.</span>
    <span class="n">expiry_year</span><span class="p">:</span> <span class="nb">str</span>

    <span class="c1">#: 3-digit card verification code.</span>
    <span class="n">cvc</span><span class="p">:</span> <span class="nb">str</span>

    <span class="k">def</span> <span class="nf">to_json</span><span class="p">(</span><span class="bp">self</span><span 