$_params
$_params : array
Params.
Returns parent documents having child docs matching the query.
This function can be used to handle params for queries, filter
__construct(string|\Elastica\Query|\Elastica\Filter\AbstractFilter $query, string|\Elastica\Type $type = null)
Construct HasChild filter.
| string|\Elastica\Query|\Elastica\Filter\AbstractFilter | $query | Query string or a Elastica\Query object or a filter | 
| string|\Elastica\Type | $type | Child document type | 
setQuery(string|\Elastica\Query|\Elastica\Query\AbstractQuery  $query) : $this
                Sets query object.
| string|\Elastica\Query|\Elastica\Query\AbstractQuery | $query | 
setFilter(\Elastica\Filter\AbstractFilter  $filter) : $this
                Sets the filter object.
| \Elastica\Filter\AbstractFilter | $filter | 
setType(string|\Elastica\Type  $type) : $this
                Set type of the child document.
| string|\Elastica\Type | $type | Child document type |