code: private boolean satisfied(final CLClause c) {
          if (c.satisfied()) { return true; }
          for (int i = 0; i < c.lits().size(); i++) {
              if (val(c.lits().get(i)) == VALUE_TRUE) {
                  if (this.level == 0) { c.setSatisfied(true); }
                  return true;
              }
          }
          return false;
      }
docs: Returns {@code true} if a given clause is satisfied, {@code false} otherwise.
  @param c the clause
  @return {@code true} if a given clause is satisfied