<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def disable(cls, user_id, github_id, name):
 """Disable webhooks for a repository. Disables the webhook from a repository if it exists in the DB. :param user_id: User identifier. :param repo_id: GitHub id of the repository. :param name: Fully qualified name of the repository. """

        repo = cls.get(user_id, github_id=github_id, name=name)
        repo.hook = None
        repo.user_id = None
        return repo