docs: def add_deploy_key(self, auth, username, repo_name, title, key_content):
          """
          Add a deploy key to the specified repo.
  
          :param auth.Authentication auth: authentication object
          :param str username: username of owner of repository
          :param str repo_name: the name of the repo
          :param str title: title of the key to add
          :param str key_content: content of the key to add
          :return: a representation of the added deploy key
          :rtype: GogsRepo.DeployKey
          :raises NetworkFailure: if there is an error communicating with the server
          :raises ApiFailure: if the request cannot be serviced
          """
          data = {
              "title": title,
              "key": key_content
          }
          response = self.post("/repos/{u}/{r}/keys".format(u=username, r=repo_name), auth=auth, data=data)
          return GogsRepo.DeployKey.from_json(response.json())