'Delete quota for a tenant or for a user.
:param tenant_id: A tenant for which quota is to be deleted
:param user_id: A user for which quota is to be deleted
:returns: An instance of novaclient.base.TupleWithMeta'

def delete(self, tenant_id, user_id=None):

    if user_id:
        url = ('/os-quota-sets/%s?user_id=%s' % (tenant_id, user_id))
    else:
        url = ('/os-quota-sets/%s' % tenant_id)
    return self._delete(url)
