android/guava/src/com/google/common/collect/Ordering.java
@GwtCompatible(serializable = true)
  @Deprecated
  public static <T> Ordering<T> from(Ordering<T> ordering) {
    return checkNotNull(ordering);
  }
@GwtCompatible(serializable = true)
  @Deprecated
  public static <T> Ordering<T> from(Ordering<T> ordering) {
    return checkNotNull(ordering);
  }
Simply returns its argument.

@deprecated no need to use this