Removes all |{key: value}| entries in :prop:key_prefix of
            :prop:_client

def clear(self, match="*", count=1000):
        """ Removes all |{key: value}| entries in :prop:key_prefix of
            :prop:_client
        """
        cursor = '0'
        while cursor != 0:
            cursor, keys = self.scan(cursor=cursor, match=match, count=count)
            if keys:
                self._client.delete(*keys)