   }
   
   public var _base: Base
-  internal var _transform: (Base.Generator.Element) -> Element
+  internal let _transform: (Base.Generator.Element) -> Element
 
   @available(*, unavailable, renamed="Element")
   public typealias T = Element

  }
  
  public var _base: Base
  var _transform: (Base.Generator.Element) -> Element

  @available(*, unavailable, renamed="Element")
  public typealias T = Element

  public var base: Base { return _base }
  
  internal var _base: Base
  internal let _transform: (Base.Element) -> Element
}

/// A `SequenceType` whose elements consist of those in a `Base`
