# Wrapper for `mongoc_collection_aggregate()`.
	#
	# This function shall execute an aggregation `pipeline` on the underlying collection.
	#
	# The `pipeline` parameter should contain a field named `pipeline` containing
	# a BSON array of pipeline stages.
	fun aggregate(pipeline: NativeBSON): nullable NativeMongoCursor import
		NativeMongoCursor.as nullable, set_mongoc_error `{
		bson_error_t error;
		mongoc_cursor_t	*cursor;
		cursor = mongoc_collection_aggregate(self, MONGOC_QUERY_NONE, pipeline, NULL, NULL);
		if (mongoc_cursor_error(cursor, &error)) {
			NativeMongoCollection_set_mongoc_error(self, &error);
			return null_NativeMongoCursor();
		}
		return NativeMongoCursor_as_nullable(cursor);
	`}