Executes the query and yields items.

def _execute(self):
        """Executes the query and yields items."""

        query = [
            'gerrit', 'query',
            '--current-patch-set',
            str(self._filters),
            '--format=JSON']

        results = self.client.exec_command(' '.join(query))
        stdin, stdout, stderr = results

        for line in stdout:
            normalized = json.loads(line)

            # Do not return the last item
            # since it is the summary of
            # of the query
            if "rowCount" in normalized:
                raise StopIteration

            yield normalized