title: External Type for Type Checking without importing the external Type
body: <p>I want to annotate my code with a Type from an external library, without actually importing the external type. Currently I'm doing this:</p>
  
  <pre><code>from externalLibrary import ExternalType # Don't want this import
  
  class MyClass:
           var: ExternalType 
  </code></pre>
  
  <p>The application that brought this up was a python dataclass, and the external Type isn't always used. But importing it always happens, and it's slow.</p>
  
  <p>Is there a way to avoid the slow import?</p>