code: public static void toDNF(LogicClause topNode)
    {
      
      while(makeDNF(topNode) == false)
      {
        // do nothing, just repeat
      }
      cleanEmptyLeafs(topNode);
      flattenDNF(topNode);
    }
docs: Transforms an AQL query to the Disjunctive Normal Form.
  @param topNode
  @return