     /// - parameter rhs: The element to append.
     ///
     /// - returns: A new sequence constructed by appending the new element to the end of the base sequence.
-    public static func + (lhs: Self, rhs: Iterator.Element) -> AnySequence<Iterator.Element> {
+    internal static func + (lhs: Self, rhs: Iterator.Element) -> AnySequence<Iterator.Element> {
         
         let oneElementSequence = AnySequence([rhs])
         

//
//

public extension Sequence {
    
    /// Concatenates the sequences.
    ///

    /// - parameter rhs: The sequence to concatenate to the base sequence.
    ///
    /// - returns: A new sequence constructed by concatenating the two sequences.
    internal static func + (lhs: Self, rhs: Self) -> AnySequence<Iterator.Element> {
        
        var lhsIterator = lhs.makeIterator()
        var rhsIterator = rhs.makeIterator()
