TypeError: object of type 'NoneType' has no len()

[Jonathan Lange]

On quantal::

$ sudo add-apt-repository ppa:undistract-me-packagers/daily
You are about to add the following PPA to your system:
 Builds of https://launchpad.net/undistract-me
 More info: https://launchpad.net/~undistract-me-packagers/+archive/daily
Press [ENTER] to continue or ctrl-c to cancel adding it

Exception in thread Thread-1:
Traceback (most recent call last):
  File "/usr/lib/python3.2/threading.py", line 740, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 141, in run
    self.add_ppa_signing_key(self.ppa_path)
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 223, in add_ppa_signing_key
    tmp_keyring, tmp_secret_keyring, signing_key_fingerprint, tmp_keyring_dir):
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 145, in _recv_key
    if not verify_keyid_is_v4(signing_key_fingerprint):
  File "/usr/lib/python3/dist-packages/softwareproperties/ppa.py", line 126, in verify_keyid_is_v4
    return len(signing_key_fingerprint) >= 160/8
TypeError: object of type 'NoneType' has no len()

At this point, the new entry in /etc/apt/sources.list.d/, but the key has not been added.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: python-software-properties 0.92.9
ProcVersionSignature: Ubuntu 3.5.0-15.23-generic 3.5.4
Uname: Linux 3.5.0-15-generic x86_64
ApportVersion: 2.6.1-0ubuntu1
Architecture: amd64
Date: Wed Oct 3 18:26:48 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta amd64 (20120301)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_GB:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: software-properties
UpgradeStatus: Upgraded to quantal on 2012-08-19 (45 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.