let regex = NSRegularExpression(pattern: pattern, options: .allZeros, error: nil)

do {
    let regex = try NSRegularExpression(pattern: pattern, options: [])
} catch {
}

do {
    let regex = try NSRegularExpression(pattern: pattern)
} catch {
}

let regex = try! NSRegularExpression(pattern: pattern, options: [])

let regex = try! NSRegularExpression(pattern: pattern)

public init(pattern: String, options: NSRegularExpression.Options = []) throws