code: @SuppressWarnings("unchecked")
      public static <T> T asType(File f, Class<T> c) {
          if (c == Writable.class) {
              return (T) asWritable(f);
          }
          return DefaultGroovyMethods.asType((Object) f, c);
      }
docs: Converts this File to a {@link groovy.lang.Writable} or delegates to default
  {@link DefaultGroovyMethods#asType(java.lang.Object, java.lang.Class)}.
  
  @param f a File
  @param c the desired class
  @return the converted object
  @since 1.0