title: Django: can't subtract offset-naive and offset-aware datetimes
body: <p>i have a 'free_trial' function in my app that allows users who have an account not older than 7 days to try my app.</p>
  <p>user model</p>
  <pre><code>from datetime import datetime, timedelta
  
      class CustomUser(AbstractUser):
      
          def free_trial(self):
              if (self.date_joined - datetime.now()) &lt; timedelta(days=7):
                  return True
                      
  </code></pre>
  <p>templates</p>
  <pre><code>{% if user.free_trial %}
  
  #Access Features
  
  {% endif %}
  </code></pre>
  <p>but i'm getting this error on template <code>can't subtract offset-naive and offset-aware datetimes</code></p>