I'm sending you a small patch to pgdb.py module. This

I'm sending you a small patch to pgdb.py module.  This
raises pgdb.DatabaseError when any of the fetch*
methods was invoked but previous call to execute* did
not produce any result set or no call was issued yet.
Also, raises pgdb.NotSupportedError when .nextset() is
invoked, instead of NameError.

This behaviour complies with DB-API 2.0.

Thanks for your work!

Timur Irmatov.