code: private static Cycles _invoke(CycleFinder finder, IAtomContainer container, int length) {
          try {
              return finder.find(container, length);
          } catch (Intractable e) {
              throw new RuntimeException("Cycle computation should not be intractable: ", e);
          }
      }
docs: Internal method to wrap cycle computations which <i>should</i> be
  tractable. That is they currently won't throw the exception - if the
  method does throw an exception an internal error is triggered as a sanity
  check.
  
  @param finder    the cycle finding method
  @param container the molecule to find the cycles of
  @param length    maximum size or cycle to find
  @return the cycles of the molecule