code: public void registerTypeface(String typefaceName, AssetManager assets, String filePath) {
          Typeface typeface = Typeface.createFromAsset(assets, filePath);
          mTypefaces.put(typefaceName, typeface);
      }
docs: This is a shortcut to let {@code CustomTypeface} create directly a {@link Typeface}
  for you. This will create the Typeface from a file located in the assets directory.
  For more information see the {@link #registerTypeface(String, Typeface)} method.
  
  @param typefaceName a name that will identify this {@code Typeface}
  @param assets       a instance of {@link AssetManager}
  @param filePath     a path to a TTF file located inside the assets folder
  
  @see #registerTypeface(String, Typeface)