These are imported module spaces. You can access methods from these namespaces.
Accessing Fields
let least = std::cmp::min(3,9);Bringing Namespaces to Scope
use std::cmp:min;
let least = min(3,9);Namespaces and Default Methods
It is important to know that some methods have a namespace equivalent function.
let x = "amos".len();
let x = std::len("amos");