Arrays in JSON Mappings

spec.yaml

database: $DATAVAULT_DATABASE_URI
source:
    slug: gb_land_registry
    title: "UK Overseas Land Owners"
    url: https://www.whatdotheyknow.com/request/overseas_company_properties_titl
tables:
    - gb_land_registry
mappings:
    lands:
        schema:
            $ref: https://schema.occrp.org/generic/land.json#
        mapping:
            id:
                columns:
                    - gb_land_registry.administrative_county
                    - gb_land_registry.district
                    - gb_land_registry.title_number
                transforms:
                    - slugify
                format: 'gb:land:%s:%s:%s'
            name:
                columns:
                    - gb_land_registry.district
                    - gb_land_registry.title_number
                transforms:
                    - join
                    - clean
            parcel_number:
                column: gb_land_registry.title_number
            valuation_date:
                column: gb_land_registry.date_of_registration
            valuation:
                column: gb_land_registry.price_num
            valuation_currency:
                default: GBP
            jurisdiction_code:
                default: GB
            owners:
                mapping:
                    valuation_date:
                        column: gb_land_registry.date_of_registration
                    valuation:
                        column: gb_land_registry.price_num
                    valuation_currency:
                        default: GBP
                    owner:
                        mapping:
                            id:
                                columns:
                                    - gb_land_registry.proprietor_country_code
                                    - gb_land_registry.proprietor_name
                                transforms:
                                    - slugify
                                format: '%s:landowner:%s'
                            name:
                                column: gb_land_registry.proprietor_name
                            jurisdiction_code:
                                column: gb_land_registry.proprietor_country_code