old_contents: from types import StringTypes
  
  from sqlalchemy import create_engine
  from sqlalchemy.orm import sessionmaker
  
  from sqlalchemy import Column, Integer, String
  from sqlalchemy.orm import relationship, backref
  from sqlalchemy import ForeignKey
  
  from sfa.util.sfalogging import logger
  
  # this module is designed to be loaded when the configured db server is reachable
  # OTOH model can be loaded from anywhere including the client-side
  
  class Alchemy:
  
      def __init__ (self, config):
          dbname="sfa"
          # will be created lazily on-demand
          self._session = None
          # the former PostgreSQL.py used the psycopg2 directly and was doing
          #self.connection.set_client_encoding("UNICODE")
          # it's unclear how to achieve this in sqlalchemy, nor if it's needed at all
          # http://www.sqlalchemy.org/docs/dialects/postgresql.html#unicode
          # we indeed have /var/lib/pgsql/data/postgresql.conf where
          # this setting is unset, it might be an angle to tweak that if need be
          # try a unix socket first - omitting the hostname does the trick
          unix_url = "postgresql+psycopg2://%s:%s@:%s/%s"%\
              (config.SFA_DB_USER,config.SFA_DB_PASSWORD,config.SFA_DB_PORT,dbname)
          # the TCP fallback method
          tcp_url = "postgresql+psycopg2://%s:%s@%s:%s/%s"%\
              (config.SFA_DB_USER,config.SFA_DB_PASSWORD,config.SFA_DB_HOST,config.SFA_DB_PORT,dbname)
          for url in [ unix_url, tcp_url ] :
              try:
                  self.engine = create_engine (url)
                  self.check()
                  self.url=url
                  return
              except:
                  pass
          self.engine=None
          raise Exception,"Could not connect to database"
                  
  
      # expects boolean True: debug is ON or False: debug is OFF
      def debug (self, echo):
          self.engine.echo=echo
  
      def check (self):
          self.engine.execute ("select 1").scalar()
  
      def session (self):
          if self._session is None:
              Session=sessionmaker ()
              self._session=Session(bind=self.engine)
          return self._session
  
      def close_session (self):
          if self._session is None: return
          self._session.close()
          self._session=None
  
  ####################
  from sfa.util.config import Config
  
  alchemy=Alchemy (Config())
  engine=alchemy.engine
  dbsession=alchemy.session()
  
  
new_contents: from types import StringTypes
  
  from sqlalchemy import create_engine
  from sqlalchemy.orm import sessionmaker
  
  from sqlalchemy import Column, Integer, String
  from sqlalchemy import ForeignKey
  
  from sfa.util.sfalogging import logger
  
  # this module is designed to be loaded when the configured db server is reachable
  # OTOH model can be loaded from anywhere including the client-side
  
  class Alchemy:
  
      def __init__ (self, config):
          dbname="sfa"
          # will be created lazily on-demand
          self._session = None
          # the former PostgreSQL.py used the psycopg2 directly and was doing
          #self.connection.set_client_encoding("UNICODE")
          # it's unclear how to achieve this in sqlalchemy, nor if it's needed at all
          # http://www.sqlalchemy.org/docs/dialects/postgresql.html#unicode
          # we indeed have /var/lib/pgsql/data/postgresql.conf where
          # this setting is unset, it might be an angle to tweak that if need be
          # try a unix socket first - omitting the hostname does the trick
          unix_url = "postgresql+psycopg2://%s:%s@:%s/%s"%\
              (config.SFA_DB_USER,config.SFA_DB_PASSWORD,config.SFA_DB_PORT,dbname)
          # the TCP fallback method
          tcp_url = "postgresql+psycopg2://%s:%s@%s:%s/%s"%\
              (config.SFA_DB_USER,config.SFA_DB_PASSWORD,config.SFA_DB_HOST,config.SFA_DB_PORT,dbname)
          for url in [ unix_url, tcp_url ] :
              try:
                  self.engine = create_engine (url)
                  self.check()
                  self.url=url
                  return
              except:
                  pass
          self.engine=None
          raise Exception,"Could not connect to database"
                  
  
      # expects boolean True: debug is ON or False: debug is OFF
      def debug (self, echo):
          self.engine.echo=echo
  
      def check (self):
          self.engine.execute ("select 1").scalar()
  
      def session (self):
          if self._session is None:
              Session=sessionmaker ()
              self._session=Session(bind=self.engine)
          return self._session
  
      def close_session (self):
          if self._session is None: return
          self._session.close()
          self._session=None
  
  ####################
  from sfa.util.config import Config
  
  alchemy=Alchemy (Config())
  engine=alchemy.engine
  dbsession=alchemy.session()
  
  
subject: remove unused import