title: How to typehint custom classes with mypy
body: <p>Given the following few modules:</p>
  <pre class="lang-py prettyprint-override"><code># mod_1.py
  from dataclasses import dataclass
  
  @dataclass
  class C:
      x : int
  </code></pre>
  <pre class="lang-py prettyprint-override"><code># mod_2.py
  from mod_1 import C
  
  c = C(x = 3)
  </code></pre>
  <pre class="lang-py prettyprint-override"><code># mod_3.py
  from mod_2 import c
  
  def f(something : &lt;type c&gt;) -&gt; None:
      print(c.x)
  </code></pre>
  <p>I'm wondering what should be put in place of <code>&lt;type c&gt;</code></p>