async def check_repo_quota(self, image_name, repo_config, repo_url):
        """
        Check whether launching a repository would exceed a quota.

        Parameters
        ----------
        image_name: str
        repo_config: dict
        repo_url: str

        Returns
        -------
        If quotas are disabled returns None
        If quotas are exceeded raises LaunchQuotaExceeded
        Otherwise returns:
          - total servers
          - matching servers running image_name
          - quota
        """
        return None

        Check whether launching a repository would exceed a quota.

        Parameters
        ----------
        image_name: str
        repo_config: dict
        repo_url: str

        Returns
        -------
        If quotas are disabled returns None
        If quotas are exceeded raises LaunchQuotaExceeded
        Otherwise returns:
          - total servers
          - matching servers running image_name
          - quota
        
binderhub/quota.py