I was building GnuCash on Windows and I got this error:

```--------------------------
  File "/c/gcdev64/src/jhbuild.git/jhbuild/utils/packagedb.py", line 79, in write
    writer.fp.write('\n'.join(self.manifest).encode('utf-8', 'backslashreplace') + b'\n')
TypeError: can only join an iterable
```

--------------------------
I fixed it adding a missing underscore on self._manifest
2 jobs for fabrica64-master-patch-64650 in 11 minutes and 55 seconds (queued for 8 seconds)
latest
Status Job ID Name Coverage
  Test
passed test-py3 #1407634

00:02:58

passed ub20.04-py3-glib #1407635

00:11:54