TIL imgaug library for augmenting images

Interesting to explore why this compiles:

extension Array where Element: Equatable {
    // For empty array returns false
    var allEqual: Bool {
        if let firstElem = first {
            return !dropFirst().contains { $0 != firstElem }
        }
        return false
    }
}

While this isn’t:

extension Array where Element == Equatable {
    // For empty array returns false
    var allEqual: Bool {
        if let firstElem = first {
            return !dropFirst().contains { $0 != firstElem }
        }
        return false
    }
}

Giving error Binary operator '!=' cannot be applied to two 'Equatable' operands.

Came across library imgaug for augmenting images. Great that it deals with bounding boxes! That exactly what I need (contains referral for 100$ at digitalocean).