'Given a list of resources, retrieve the default quotas.
Use the class quotas named `_DEFAULT_QUOTA_NAME` as default quotas,
if it exists.
:param context: The request context, for access checks.
:param resources: A dictionary of the registered resources.'

def get_defaults(self, context, resources):

    quotas = {}
    default_quotas = objects.Quotas.get_default_class(context)
    for resource in resources.values():
        quotas[resource.name] = default_quotas.get(resource.name, resource.default)
    return quotas
