Comment 12 for bug 620458

I can confirm it's fixed:

In [7]: from launchpadlib.uris import LPNET_SERVICE_ROOT
In [8]: from launchpadlib.launchpad import Launchpad
In [9]: lp = Launchpad.login_with("testing", LPNET_SERVICE_ROOT, "/tmp/lp", version="devel")
[...]
In [10]: b = lp.bugs[622597]
In [11]: b.attachments[0].data
Out[11]: <lazr.restfulclient.resource.HostedFile object at 0x2928a90>
In [12]: f = b.attachments[0].data.open()
In [13]: f
Out[13]: <lazr.restfulclient.resource.HostedFileBuffer instance at 0x2921a28>