docs: def verify_signature(self, payload, headers):
          """Verify that the payload was sent from our GitHub instance."""
          github_signature = headers.get("x-hub-signature")
          if not github_signature:
              json_abort(401, "X-Hub-Signature header missing.")
  
          gh_webhook_secret = current_app.config["GITHUB_WEBHOOK_SECRET"]
          signature = "sha1={}".format(
              hmac.new(
                  gh_webhook_secret.encode("utf-8"), payload, hashlib.sha1
              ).hexdigest()
          )
  
          if not hmac.compare_digest(signature, github_signature):
              json_abort(401, "Request signature does not match calculated signature.")