product.metafields.custom["size"] =>
product.metafields.custom.size => 8

product.metafields.custom["first"] =>
product.metafields.custom.first => bundle_product_list["gid://shopify/Product/7504794419222","gid://shopify/Product/7504794583062","gid://shopify/Product/7504794648598","gid://shopify/Product/7504794517526"]

product.metafields.custom["last"] =>
product.metafields.custom.last =>

product.metafields.custom["to_h"] =>
product.metafields.custom.to_h =>

product.metafields.custom["to_liquid"] =>
product.metafields.custom.to_liquid =>