title: Python requests - retry for any status code but not 400
body: <p>I am using the following snippet(please note, only partial snippets shown):</p>
  
  <pre><code>from urllib3.util import Retry
  status_forcelist = (500, 502, 504)
  
  
  retry = Retry(
          total=retries,
          read=retries,
          connect=retries,
          backoff_factor=backoff_factor,
          status_forcelist=status_forcelist,
          method_whitelist=frozenset(['GET', 'POST'])
  </code></pre>
  
  <p>As of now, the retry would be done for status codes <code>500</code>,<code>502</code>,<code>504</code>. However, I intend to retry for any status code but not <code>400</code>. Is there a graceful way to achieve this instead of populating/hardcoding the <code>status_forcelist</code> for all status codes  ?</p>