code: def confirm_email_view(self, token):
          
          # Verify token
          data_items = self.token_manager.verify_token(
              token,
              self.USER_CONFIRM_EMAIL_EXPIRATION)
  
          # Retrieve user, user_email by ID
          user = None
          user_email = None
          if data_items:
              user, user_email = self.db_manager.get_user_and_user_email_by_id(data_items[0])
  
          if not user or not user_email:
              flash(_('Invalid confirmation token.'), 'error')
              return redirect(url_for('user.login'))
  
          # Set UserEmail.email_confirmed_at
          user_email.email_confirmed_at=datetime.utcnow()
          self.db_manager.save_user_and_user_email(user, user_email)
          self.db_manager.commit()
  
          # Send confirmed_email signal
          signals.user_confirmed_email.send(current_app._get_current_object(), user=user)
  
          # Flash a system message
          flash(_('Your email has been confirmed.'), 'success')
  
          # Auto-login after confirm or redirect to login page
          safe_next_url = self._get_safe_next_url('next', self.USER_AFTER_CONFIRM_ENDPOINT)
          if self.USER_AUTO_LOGIN_AFTER_CONFIRM:
              return self._do_login_user(user, safe_next_url)  # auto-login
          else:
              return redirect(url_for('user.login') + '?next=' + quote(safe_next_url))
docs: Verify email confirmation token and activate the user account.