code: private static Variable[] litsAsVars(final Literal[] lits) {
      final Variable[] vars = new Variable[lits.length];
      for (int i = 0; i < vars.length; i++)
        vars[i] = lits[i].variable();
      return vars;
    }
docs: Converts a literal array to a variable array
  <p>
  ATTENTION: this only works if because the {@code isCC} method checks, that there are only positive literals.
  @param lits the literals
  @return the variables