<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def select(self, db):
 """Change the selected database for the current connection."""

        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)