Convert the “facet_filter” query into pyes format

I have a following query and I want to change that query into PyES:

{
"facets": {
"participating-org.name": {
"terms": {
"field": "participating-org.name"
},
"facet_filter": {
"term": {
"participating-org.role": "funding"
}
},
"nested": "participating-org"
}
}
}

I have searched in PyES documentation about this "facet_filter" but
couldn't come up with good query in PyES.
So need some HELP for converting this JSON query into PyES format.

--