UIFont Extension for Custom Dynamic Font

UIFont+CustomFont.swift

import UIKit

extension UIFont {
    class func preferredCustomFontForTextStyle (textStyle: NSString) -> UIFont {
        let fontsDictionary = NSDictionary (contentsOfFile: NSBundle.mainBundle().pathForResource("CustomFontNames", ofType: "plist")!)
        let font = UIFontDescriptor.preferredFontDescriptorWithTextStyle(textStyle)
        let fontSize: CGFloat = font.pointSize

        if textStyle == UIFontTextStyleHeadline || textStyle == UIFontTextStyleSubheadline {
            if let boldFontName = (fontsDictionary.valueForKey("Bold Font Name") as String?) {
                return UIFont(name: boldFontName, size: fontSize)
            }
            else {
                NSLog("Fonts.plist is missing a value for the “Bold Font” key?")
                return UIFont.boldSystemFontOfSize(fontSize)
            }
        }
        else {
            if let regularFontName = (fontsDictionary.valueForKey("Regular Font Name") as String?) {
                return UIFont(name: regularFontName, size: fontSize)
            }
            else {
                NSLog("Fonts.plist is missing a value for the “Regular Font” key?")
                return UIFont.systemFontOfSize(fontSize)
            }
        }
    }
}

Why Line 9 if we have same type of assignment in Line 22 ?