 public extension SequenceType where Generator.Element : Equatable {
     
     /// Return `true` if all of elements in `seq` is `x`.
+    ///
+    /// - Complexity: O(`self.count`).
     @warn_unused_result
     func all(x: Generator.Element) -> Bool {
         

public extension CollectionType where Index : BidirectionalIndexType {
    
    /// Return last of elements in `seq` satisfies `predicate`.
    @warn_unused_result
    func lastOf(@noescape predicate: (Generator.Element) throws -> Bool) rethrows -> Generator.Element? {
        
        return try self.reverse().firstOf(predicate)
    }
}

public extension SequenceType {
    
    /// Return `true` if all of elements in `seq` satisfies `predicate`.
    ///
    /// - Complexity: O(`self.count`).
    @warn_unused_result
    func all(@noescape predicate: (Generator.Element) throws -> Bool) rethrows -> Bool {
        
