python-sqlalchemy: Conflicts: python-psycopg but 1.1.21-15ubuntu1 is to be installed.

sudo aptitude install python-psycopg
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The following packages are BROKEN:
  python-sqlalchemy
The following NEW packages will be installed:
  python-psycopg
0 packages upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 166kB of archives. After unpacking 401kB will be used.
The following packages have unmet dependencies:
  python-sqlalchemy: Conflicts: python-psycopg but 1.1.21-15ubuntu1 is to be installed.
Resolving dependencies...
The following actions will resolve these dependencies:

Remove the following packages:
python-sqlalchemy
python-sqlalchemy-doc

Score is -172

Accept this solution? [Y/n/q/?] q
Abandoning all efforts to resolve these dependencies.
Abort.