def scan_aggs(search, source_aggs, inner_aggs={}, size=10):
    """
    Helper function used to iterate over all possible bucket combinations of
    ``source_aggs``, returning results of ``inner_aggs`` for each. Uses the
    ``composite`` aggregation under the hood to perform this.
    """
    def run_search(**kwargs):
        s = search[:0]
        s.aggs.bucket('comp', 'composite', sources=source_aggs, size=size, **kwargs)
        for agg_name, agg in inner_aggs.items():
            s.aggs['comp'][agg_name] = agg
        return s.execute()

    response = run_search()
    while response.aggregations.comp.buckets:
        for b in response.aggregations.comp.buckets:
            yield b
        if 'after_key' in response.aggregations.comp:
            after = response.aggregations.comp.after_key
        else:
            after= response.aggregations.comp.buckets[-1].key
        response = run_search(after=after)