code: def select(self, db):
          
          if not isinstance(db, int):
              raise TypeError("DB must be of int type, not {!r}".format(db))
          if db < 0:
              raise ValueError("DB must be greater or equal 0, got {!r}"
                               .format(db))
          fut = self.execute('SELECT', db)
          return wait_ok(fut)
docs: Change the selected database for the current connection.