'Returns the X-[Account|Container]-Meta-Temp-URL-Key[-2] header values
for the account or container, or an empty list if none are set. Each
value comes as a 2-tuple (key, scope), where scope is either
CONTAINER_SCOPE or ACCOUNT_SCOPE.
Returns 0-4 elements depending on how many keys are set in the
account\'s or container\'s metadata.
:param env: The WSGI environment for the request.
:returns: [
(X-Account-Meta-Temp-URL-Key str value, ACCOUNT_SCOPE) if set,
(X-Account-Meta-Temp-URL-Key-2 str value, ACCOUNT_SCOPE if set,
(X-Container-Meta-Temp-URL-Key str value, CONTAINER_SCOPE) if set,
(X-Container-Meta-Temp-URL-Key-2 str value, CONTAINER_SCOPE if set,'

def _get_keys(self, env):

    account_info = get_account_info(env, self.app, swift_source='TU')
    account_keys = get_tempurl_keys_from_metadata(account_info['meta'])
    container_info = get_container_info(env, self.app, swift_source='TU')
    container_keys = get_tempurl_keys_from_metadata(container_info.get('meta', []))
    return ([(ak, ACCOUNT_SCOPE) for ak in account_keys] + [(ck, CONTAINER_SCOPE) for ck in container_keys])
