code: public <T> T pluck (Iterable<? extends T> iterable, T ifEmpty)
      {
          return pickPluck(iterable, ifEmpty, true);
      }
docs: Pluck (remove) a random element from the specified Iterable, or return <code>ifEmpty</code>
  if it is empty.
  
  <p><b>Implementation note:</b> optimized implementations are used if the Iterable
  is a List or Collection. Otherwise, two Iterators are created from the Iterable
  and a random number is generated after the second element and all beyond.
  
  @throws NullPointerException if the iterable is null.
  @throws UnsupportedOperationException if the iterable is unmodifiable or its Iterator
  does not support {@link Iterator#remove()}.