这是执行的日志记录arc diff：
$ arc diff --trace
ARGV '/Users/yangyan/Meican/arcanist/bin/../scripts/arcanist.php' 'diff' '--trace'
LOAD Loaded "phutil" from "/Users/yangyan/Meican/libphutil/src".
LOAD Loaded "arcanist" from "/Users/yangyan/Meican/arcanist/src".
Config: Reading user configuration file "/Users/yangyan/.arcrc"...
Config: Did not find system configuration at "/etc/arcconfig".
Working Copy: Reading .arcconfig from "/Users/yangyan/Meican/go/src/code.meican.com/diffusion/DEMETER/demeter.git/.arcconfig".
Working Copy: Path "/Users/yangyan/Meican/go/src/code.meican.com/diffusion/DEMETER/demeter.git" is part of `git` working copy "/Users/yangyan/Meican/go/src/code.meican.com/diffusion/DEMETER/demeter.git".
Working Copy: Project root is at "/Users/yangyan/Meican/go/src/code.meican.com/diffusion/DEMETER/demeter.git".
Config: Did not find local configuration at "/Users/yangyan/Meican/go/src/code.meican.com/diffusion/DEMETER/demeter.git/.git/arc/config".
>>> [0] <conduit> user.whoami() <bytes = 117>
>>> [1] <http> https://code.meican.com/api/user.whoami
<<< [1] <http> 636,235 us
<<< [0] <conduit> 636,726 us
[2016-04-01 06:33:53] EXCEPTION: (ConduitClientException) ERR-INVALID-SESSION: Session key is not present. at [<phutil>/src/conduit/ConduitFuture.php:58]
arcanist(head=master, ref.master=fcc11b3a2781), phutil(head=master, ref.master=3024f0a4908b)
#0 ConduitFuture::didReceiveResult(array) called at [<phutil>/src/future/FutureProxy.php:58]
#1 FutureProxy::getResult() called at [<phutil>/src/future/FutureProxy.php:35]
#2 FutureProxy::resolve() called at [<phutil>/src/conduit/ConduitClient.php:58]
#3 ConduitClient::callMethodSynchronous(string, array) called at [<arcanist>/src/workflow/ArcanistWorkflow.php:332]
#4 ArcanistWorkflow::authenticateConduit() called at [<arcanist>/scripts/arcanist.php:354]
我应该如何处理以下错误？
配置：未在“/etc/arcconfig”找到系统配置。配置：未在“/Users/yangyan/Meican/go/src/code.meican.com/diffusion/DEMETER/demeter.git/.git/arc/config”找到本地配置。