code: public Runnable compose(Runnable runnableOne, Runnable runnableTwo) {
  
      return runnableOne == null ? runnableTwo : (runnableTwo == null ? runnableOne
        : new ComposableRunnable(runnableOne, runnableTwo));
    }
docs: Composes two {@link Runnable} objects into a single, compound {@link Runnable} object.
  
  Returns the {@code runnableOne} if {@code runnableTwo} is {@literal null}
  and {@code runnableTwo} if the {@code runnableOne} is {@literal null}.
  
  @param runnableOne {@link Runnable} object in the composition.
  @param runnableTwo {@link Runnable} object in the composition.
  @return a {@link Runnable} object composed with the given left and right {@link Runnable} objects.
  @see java.lang.Runnable