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I'm using NSClassFromString to create a class type. But I do not have the type as ClassName.Type, only as a string. Although, I'm sure this class will be with SourceProtocol. And I want to call functions of this protocol. How can I do it? I tried casting to this protocol. But protocol doesn't have inits. Therefore I can't use functions. And here's example import Cocoa protocol NeededMethods { func doSmt(str: String) -> String } struct FirstImplementation: NeededMethods { func doSmt(str: String) -> String { str.replacingOccurrences(of: "1", with: "0") } } let anyclass = NSClassFromString("FirstImplementation") I want to call doSmt,  without using FirstImplementation.Type (because it can be any class, not only FirstImplementatioon)