code: public F0<R> orElse(final Func0<? extends R> fallback) {
              final F0<R> me = this;
              return new F0<R>() {
                  @Override
                  public R apply() {
                      try {
                          return me.apply();
                      } catch (RuntimeException e) {
                          return fallback.apply();
                      }
                  }
              };
          }
docs: Returns a composed function that when applied, try to apply this function first, in case
  a {@link java.lang.RuntimeException} is captured apply to the fallback function specified. This
  method helps to implement partial function
  
  @param fallback
  the function to applied if this function doesn't apply in the current situation
  @return the final result