         return constraints
     }
 
+    // MARK: Private helper methods.
     private func anchor(for anchor: HorizontalAnchor) -> NSLayoutAnchor<NSLayoutXAxisAnchor> {
         switch anchor {
         case .leading:

        return constraint
    }

    @discardableResult
    func pin(_ edge: VerticalAnchor, to anchorAttachment: NSLayoutAnchor<NSLayoutYAxisAnchor>, padding: CGFloat = 0.0) -> NSLayoutConstraint {
        let constraint = anchor(for: edge).constraint(equalTo: anchorAttachment, constant: padding)

        return constraint
    }

    /// Pin the specified `DimensionAnchor` of the view to a fixed size. Calling this method sets `translatesAutoresizingMaskIntoConstraints` to `false` on the caller.
    ///
    /// - Parameters:
    ///   - dimension: `DimensionAnchor` of the caller to pin to. Either `width` or `height`.
    ///   - size: Size to pin the `DimensionAnchor` to.
    /// - Returns: The activated `NSLayoutConstraint` object that was created.
    @discardableResult
    func pin(_ dimension: DimensionAnchor, size: CGFloat) -> NSLayoutConstraint {
        let constraint = anchor(for: dimension).constraint(equalToConstant: size)
