Instance Method
add(_:required:customFailureDescription:_:)
mutating func add(_ key: ValidationKey, required: Bool = true, customFailureDescription: String? = nil, _ nested: (inout Validations) -> ())
Instance Method
mutating func add(_ key: ValidationKey, required: Bool = true, customFailureDescription: String? = nil, _ nested: (inout Validations) -> ())