当我在 Ubuntu 16.10 中运行时：
$ umake android --accept-license
ERROR: https://developer.android.com/sdk/index.html couldn't finish download: HTTPSConnectionPool(host='developer.android.com', port=443): Max retries exceeded with url: /sdk/index.html (Caused by ProxyError('Cannot connect to proxy.', RemoteDisconnected('Remote end closed connection without response',)))
ERROR: An error occurred while downloading https://developer.android.com/sdk/index.html: HTTPSConnectionPool(host='developer.android.com', port=443): Max retries exceeded with url: /sdk/index.html (Caused by ProxyError('Cannot connect to proxy.', RemoteDisconnected('Remote end closed connection without response',)))
这似乎是代理问题，但我使用 apt 时没有遇到任何问题。我该如何设置 umake 的代理值？
我的umake版本是16.05