I'm trying to make a formula and I got the error: $ operator not defined for this S4 class with R. First of all, what is a S4 class? What am I doing wrong
html-select
simplebar
angular-guards
http-referer
android-jetpack-compose-text
altitude
pager
fql.multiquery
packetbeat
tensorflow-slim
google-maps-api-2
cxf-client
mobiledevice.framework
autodesk-webhooks
epsg
hubspot-cms
tibco
unity-test-tools
webrtc-android
protobufjs
nhydrate
nestjs-swagger
aws.s3
analyzer
set-returning-functions
delphi
.net-standard
single-file
logstash-logback-encoder
caching
