title: What is the meaning of -> List[int] in this function declaration?
body: <p>I want to understand the declaration of this function: <code>-&gt;List[int]:</code></p>
  <p>I have learned the basics of Python and I never saw function declaration like this before</p>
  <pre class="lang-py prettyprint-override"><code>class Solution:
      def twoSum(self, nums: List[int], target: int) -&gt; List[int]:
  </code></pre>