Recall from [Enabling runtime checks](/docs/runtime) that `sorbet-runtime` raises| sorbet.org
This is one of three docs aimed at helping answer common questions about Sorbet:| sorbet.org
The type `T.untyped` represents a type that Sorbet has no specific knowledge| sorbet.org
```ruby| sorbet.org
`T.attached_class` can be used to refer to the type of instances from a| sorbet.org
Sorbet can track when a value is allowed to be `nil`, or when a value of a| sorbet.org