Delete all keys in all databases on the current host.

        ``asynchronous`` indicates whether the operation is
        executed asynchronously by the server.

def flushall(self, asynchronous=False):
        """
        Delete all keys in all databases on the current host.

        ``asynchronous`` indicates whether the operation is
        executed asynchronously by the server.
        """
        args = []
        if asynchronous:
            args.append(Token.get_token('ASYNC'))
        return self.execute_command('FLUSHALL', *args)