associatedtype in swift explanation with example

ModelManager.swift

protocol ModelManager {
	associatedtype NewModel
	associatedtype Collection: Swift.Collection where Collection.Element == NewModel
	associatedtype Query
	
	func models(matching query: Query) -> Collection
}

User.swift

struct User {
	var name: String
	var age: Int
}

UserManager.swift

class UserManager: ModelManager {
	typealias NewModel = User
	var allUsers: [User]!
	enum Query {
		case name(String)
		case ageRange(Range<Int>)
	}
	
	func models(matching query: Query) -> [User] {
		switch query {
			case .name(let name):
				return allUsers.filter({$0.name.contains(name)})
			case .ageRange(let ageRange):
//				return allUsers.filter({$0.age > ageRange.lowerBound && $0.age < ageRange.upperBound})
				return allUsers.filter({ageRange.contains($0.age)})
		}
	}
}