I attempted to upgrade to Ubuntu 17.04 zesty.  That seems to have failed.  Now, when I do `sudo aptitude full-upgrade`, I get the following error messages:

# =====================================================================
The following packages will be upgraded:
  python3
The following partially installed packages will be configured:
  gedit python3-minimal python3-uno python3.5 python3.5-minimal
  rhythmbox-plugin-magnatune rhythmbox-plugins ubuntu-gnome-desktop
1 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/8,696 B of archives. After unpacking 0 B will be used.
Do you want to continue? [Y/n/?]
Setting up python3.5-minimal (3.5.3-1) ...
Traceback (most recent call last):
  File "/usr/lib/python3.5/py_compile.py", line 6, in <module>
    import importlib._bootstrap_external
  File "/usr/lib/python3.5/importlib/__init__.py", line 57, in <module>
    import types
  File "/usr/lib/python3.5/types.py", line 166, in <module>
    import functools as _functools
  File "/usr/lib/python3.5/functools.py", line 23, in <module>
    from weakref import WeakKeyDictionary
  File "/usr/lib/python3.5/weakref.py", line 12, in <module>
    from _weakref import (
ImportError: cannot import name '_remove_dead_weakref'
dpkg: error processing package python3.5-minimal (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of python3-minimal:
 python3-minimal depends on python3.5-minimal (>= 3.5.3-1~); however:
  Package python3.5-minimal is not configured yet.

dpkg: error processing package python3-minimal (--configure):
 dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.
                Errors were encountered while processing:
 python3.5-minimal
 python3-minimal
E: Sub-process /usr/bin/dpkg returned an error code (1)
Setting up python3.5-minimal (3.5.3-1) ...
Traceback (most recent call last):
  File "/usr/lib/python3.5/py_compile.py", line 6, in <module>
    import importlib._bootstrap_external
  File "/usr/lib/python3.5/importlib/__init__.py", line 57, in <module>
    import types
  File "/usr/lib/python3.5/types.py", line 166, in <module>
    import functools as _functools
  File "/usr/lib/python3.5/functools.py", line 23, in <module>
    from weakref import WeakKeyDictionary
  File "/usr/lib/python3.5/weakref.py", line 12, in <module>
    from _weakref import (
ImportError: cannot import name '_remove_dead_weakref'
dpkg: error processing package python3.5-minimal (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of python3-minimal:
 python3-minimal depends on python3.5-minimal (>= 3.5.3-1~); however:
  Package python3.5-minimal is not configured yet.

dpkg: error processing package python3-minimal (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of python3.5:
 python3.5 depends on python3.5-minimal (= 3.5.3-1); however:
  Package python3.5-minimal is not configured yet.

dpkg: error processing package python3.5 (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of rhythmbox-plugins:
 rhythmbox-plugins depends on python3.5; however:
  Package python3.5 is not configured yet.

dpkg: error processing package rhythmbox-plugins (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of rhythmbox-plugin-magnatune:
 rhythmbox-plugin-magnatune depends on rhythmbox-plugins; however:
  Package rhythmbox-plugins is not configured yet.

dpkg: error processing package rhythmbox-plugin-magnatune (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of python3-uno:
 python3-uno depends on python3.5; however:
  Package python3.5 is not configured yet.

dpkg: error processing package python3-uno (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of gedit:
 gedit depends on python3.5; however:
  Package python3.5 is not configured yet.

dpkg: error processing package gedit (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of ubuntu-gnome-desktop:
 ubuntu-gnome-desktop depends on gedit; however:
  Package gedit is not configured yet.

dpkg: error processing package ubuntu-gnome-desktop (--configure):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 python3.5-minimal
 python3-minimal
 python3.5
 rhythmbox-plugins
 rhythmbox-plugin-magnatune
 python3-uno
 gedit
 ubuntu-gnome-desktop
# =====================================================================