android/guava/src/com/google/common/graph/ImmutableNetwork.java
@Deprecated
  public static <N, E> ImmutableNetwork<N, E> copyOf(ImmutableNetwork<N, E> network) {
    return checkNotNull(network);
  }
@Deprecated
  public static <N, E> ImmutableNetwork<N, E> copyOf(ImmutableNetwork<N, E> network) {
    return checkNotNull(network);
  }
Simply returns its argument.

@deprecated no need to use this