code: private List<Cycle> membersOfBasis(final List<Cycle> cycles) {
          int start = basis.size();
          for (final Cycle c : cycles) {
              if (basis.isIndependent(c)) basis.add(c);
          }
          return basis.members().subList(start, basis.size());
      }
docs: For a list of equal length cycles return those which are members of the
  minimum cycle basis.
  
  @param cycles cycles to add to the basis
  @return cycles which were added to the basis