`var unformattedText: String!` `unformattedText.to...

# getting-started

[Brian S]

var unformattedText: String!
unformattedText.toLowerCase()
this one compiles,
var unformattedText: String!
unformattedText.lowercase(Locale.getDefault())
this one gives a error: Unresolved reference: lowercase (edited)
Anyone know why,
I am using kotlin_version 1.6.0
kotlin.coroutines 1.5.2
serialization 1.3.1