NachoSoto

import Foundation

extension Sequence {
    // Extension on Sequence allows us to use this method on Arrays, Maps, Sets, etc.
    func uniqueElements<Index: Hashable>(for indexer: (Element) -> Index) -> [Element] {
        // Keep track of what we've already seen in a Set,
        // which allows us to query for elements efficiently.
        var seenElements: Set<Index> = []
        
        var result: [Element] = []

NachoSoto

// Extensions to simplify usage of accessibilityTraits in Swift 4.2:

public func |= (traits: inout UIAccessibilityTraits, other: [UIAccessibilityTraits]) {
    for o in other {
        traits |= o
    }
}

public func |= (traits: inout UIAccessibilityTraits, other: UIAccessibilityTraits) {
    // From: https://swift.org/migration-guide-swift4.2/#known-migration-issues