I've managed to do something on my Debian system and Python-Cryptography won't let me install or remove anything

Here's the result of an apt update / apt upgrade / apt dist-upgrade

sudo apt dist-upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
The following packages will be upgraded:
  python-cryptography
1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
24 not fully installed or removed.
Need to get 0 B/212 kB of archives.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] y
Reading changelogs... Done
(Reading database ... 81174 files and directories currently installed.)
Preparing to unpack .../python-cryptography_1.7.1-3+deb9u2_amd64.deb ...
  File "/usr/bin/pyclean", line 63
    except (IOError, OSError), e:
                             ^
SyntaxError: invalid syntax
dpkg: warning: subprocess old pre-removal script returned error exit status 1
dpkg: trying script from the new package instead ...
  File "/usr/bin/pyclean", line 63
    except (IOError, OSError), e:
                             ^
SyntaxError: invalid syntax
dpkg: error processing archive /var/cache/apt/archives/python-cryptography_1.7.1-3+deb9u2_amd64.deb (--unpack):
 subprocess new pre-removal script returned error exit status 1
Traceback (most recent call last):
  File "/usr/bin/pycompile", line 35, in <module>
    from debpython.version import SUPPORTED, debsorted, vrepr, \
  File "/usr/share/python/debpython/version.py", line 24, in <module>
    from ConfigParser import SafeConfigParser
ImportError: No module named 'ConfigParser'
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 /var/cache/apt/archives/python-cryptography_1.7.1-3+deb9u2_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

I'm not really sure what I've actually done here, but I can't get past it. I can't seem to remove that package, or fix it, or reinstall it, everything just fails with that or a similar error. Could someone help me get rid of this damn thing please, I've been trying for a couple of days now.

Thanks!!!

Solution

I ran into this today as well, python-cryptography was blocking me in a similar way.

I ran pyclean manually on python-cryptography package. I was root so you may need to prepend sudo to the command

/usr/bin/pyclean python-cryptography

This got me to a different set of errors (unrelated to your problem most likely. My system was very broken), but dpkg was happy enough to start working again. Give it a shot

-Tom