How I can view facet view key? I have module where used this code:

$variables['facet_metal_level'] = module_invoke('facetapi', 'block_view', '8Ratyom2YlpSn79FmHOAv8S1HaSXS6HJ');


How and Where I can find this view key '8Ratyom2YlpSn79FmHOAv8S1HaSXS6HJ' ?
It's delta of block.
You can receive it via this code:

$delta = facetapi_hash_delta(facetapi_build_delta('SEARCHER@MACHINE_NAME_OF_SEARCH_INDEX', 'block', 'MACHINE_NAME_OF_FACET'));


Example:

$delta = facetapi_hash_delta(facetapi_build_delta('search_api@fr_node_index', 'block', 'field_price'));