python-pysnmp4 cannot be installed

Binary package hint: python-pysnmp4

root@alatar ~ # apt-get install python-pysnmp4
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  python-pysnmp-common python-pysnmp4-apps python-pysnmp4-mibs
Suggested packages:
  python-pysnmp4-doc
The following NEW packages will be installed:
  python-pysnmp-common python-pysnmp4 python-pysnmp4-apps python-pysnmp4-mibs
0 upgraded, 4 newly installed, 0 to remove and 11 not upgraded.
Need to get 0B/544kB of archives.
After this operation, 5,083kB of additional disk space will be used.
Do you want to continue [Y/n]?
Selecting previously deselected package python-pysnmp-common.
(Reading database ... 442082 files and directories currently installed.)
Unpacking python-pysnmp-common (from .../python-pysnmp-common_4.1.9a-1ubuntu1_all.deb) ...
Unpacking python-pysnmp4 (from .../python-pysnmp4_4.1.9a-1ubuntu1_all.deb) ...
dpkg: error processing /var/cache/apt/archives/python-pysnmp4_4.1.9a-1ubuntu1_all.deb (--unpack):
 trying to overwrite '/usr/share/pyshared/pysnmp/__init__.py', which is also in package python-pysnmp-common 4.1.9a-1ubuntu1
configured to not write apport reports
                                      Selecting previously deselected package python-pysnmp4-apps.
Unpacking python-pysnmp4-apps (from .../python-pysnmp4-apps_0.2.6a-1_all.deb) ...
Selecting previously deselected package python-pysnmp4-mibs.
Unpacking python-pysnmp4-mibs (from .../python-pysnmp4-mibs_0.0.5a-3_all.deb) ...
Processing triggers for man-db ...
Errors were encountered while processing:
 /var/cache/apt/archives/python-pysnmp4_4.1.9a-1ubuntu1_all.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: python-pysnmp4 (not installed)
ProcVersionSignature: Ubuntu 2.6.35-12.17-generic 2.6.35-rc6
Uname: Linux 2.6.35-12-generic i686
Architecture: i386
Date: Sun Aug 1 12:57:16 2010
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100427.1)
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/zsh
SourcePackage: python-pysnmp4