擅长:python、mysql、java
<ul>
<li><p><code>response = input('-')</code>这里的<code>input</code>函数将返回<code>str</code></p>
</li>
<li><p>您的dict<code>topping_mappings</code>此处的键为<code>int</code>。因此,您需要在此<code>toppings_wanted = topping_mappings[toppings_wanted]</code>之前转换为<code>int</code></p>
</li>
<li><p>以下更改是修复它的一种方法</p>
</li>
</ul>
<pre><code>response = input('-')
toppings_wanted = int(response) if response.isdigit() else None
toppings_wanted = topping_mappings[toppings_wanted]
</code></pre>