Implement `apply` on NSObject (and other types)

Applicable.swift

import Foundation

protocol Applicable {}
extension NSObject: Applicable {}

extension Applicable {
    @discardableResult
    func apply(_ closure: (Self) -> Void) -> Self {
        closure(self)
        return self
    }
}

extension Array where Element: NSObject {
    @discardableResult
    func apply(_ closure: (Element) -> Void) -> [Element] {
        forEach { closure($0) }
        return self
    }
}

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