code: def _connect(self, database=None):
          
          conn_args = {
              'host': self.config['host'],
              'user': self.config['user'],
              'password': self.config['password'],
              'port': self.config['port'],
              'sslmode': self.config['sslmode'],
          }
  
          if database:
              conn_args['database'] = database
          else:
              conn_args['database'] = 'postgres'
  
          # libpq will use ~/.pgpass only if no password supplied
          if self.config['password_provider'] == 'pgpass':
              del conn_args['password']
  
          try:
              conn = psycopg2.connect(**conn_args)
          except Exception as e:
              self.log.error(e)
              raise e
  
          # Avoid using transactions, set isolation level to autocommit
          conn.set_isolation_level(0)
          return conn
docs: Connect to given database