old_contents: from django.contrib.sites.shortcuts import get_current_site
  from django.urls import reverse
  from django.core.signing import TimestampSigner
  
  
  class BaseEngine:
      def __init__(self):
          self.signer = TimestampSigner()
  
      def get_webhook_url(self):
          return "{}://{}/{}?token={}".format(
              "https",
              get_current_site(None).domain,
              reverse("virus_scan:webhook"),
              self.signer.sign(self.name),
          )
  
      def send_scan(self, this_file, filename):
          raise NotImplementedError(
              "Provide 'send' in {name}".format(name=self.__class__.__name__)
          )
  
      def receive_scan(self, engine_id):
          raise NotImplementedError(
              "Provide 'receive_scan' in {name}".format(name=self.__class__.__name__)
          )
  
new_contents: from django.contrib.sites.shortcuts import get_current_site
  from django.urls import reverse
  from django.core.signing import TimestampSigner
  
  
  class BaseEngine:
      def __init__(self):
          self.signer = TimestampSigner()
  
      def get_webhook_url(self):
          return "{}://{}{}?token={}".format(
              "https",
              get_current_site(None).domain,
              reverse("virus_scan:webhook"),
              self.signer.sign(self.name),
          )
  
      def send_scan(self, this_file, filename):
          raise NotImplementedError(
              "Provide 'send' in {name}".format(name=self.__class__.__name__)
          )
  
      def receive_scan(self, engine_id):
          raise NotImplementedError(
              "Provide 'receive_scan' in {name}".format(name=self.__class__.__name__)
          )
  
subject: Remove duplicated slash in virus_scan