code: def _get_connection(self):
          
          if not getattr(self, '_connection', None):
              logger.debug(
                  'Creating new connection.\n   dsn: {}'
                  .format(self._dsn))
  
              d = parse_url_to_dict(self._dsn)
              self._connection = psycopg2.connect(
                  database=d['path'].strip('/'), user=d['username'], password=d['password'],
                  port=d['port'], host=d['hostname'])
              # It takes some time to find the way how to get raw connection from sqlalchemy. So,
              # I leave the commented code.
              #
              # self._engine = create_engine(self._dsn)
              # self._connection = self._engine.raw_connection()
              #
          return self._connection
docs: Returns connection to the postgres database.
  
          Returns:
              connection to postgres database who stores mpr data.