title: mypy - erroring when there are no Python files
body: <p>Is there a way to stop <code>mypy</code> erroring when it doesn't find any <code>.py</code> files? In essence, this isn't an error. What Im looking to do is hide or silence this one error.</p>
  <pre><code>$ poetry run mypy .
  There are no .py[i] files in directory '.'
  Error: Process completed with exit code 2.
  </code></pre>
  <p>Thanks,</p>