docs: def register_form_factory(Form):
      """Factory for creating an extended user registration form."""
      class CsrfDisabledProfileForm(ProfileForm):
          """Subclass of ProfileForm to disable CSRF token in the inner form.
  
          This class will always be a inner form field of the parent class
          `Form`. The parent will add/remove the CSRF token in the form.
          """
  
          def __init__(self, *args, **kwargs):
              """Initialize the object by hardcoding CSRF token to false."""
              kwargs = _update_with_csrf_disabled(kwargs)
              super(CsrfDisabledProfileForm, self).__init__(*args, **kwargs)
  
      class RegisterForm(Form):
          """RegisterForm extended with UserProfile details."""
  
          profile = FormField(CsrfDisabledProfileForm, separator='.')
  
      return RegisterForm