code: function readCaChain(caChain){
      var ret = [];
      if (caChain instanceof Array){
          caChain.forEach(function(fileName){
              try{
                  ret.push(fs.readFileSync(fileName , "utf-8"))
              }catch(e){
                  console.log("---readCaChain--- Error reading CA chain file");
                  console.log(e);
                  return null;
              }
          });
      }
      // IF it is a string, it should be directly a file name and not a chain
      if (caChain instanceof String){
          try{
              ret.push(fs.readFileSync(caChain) , "utf-8");
          }catch(e){
              console.log("---readCaChain--- Error reading CA chain file");
              console.log(e);
              return null;
          }
      }
      return ret;
  }
docs: Given an array of file name (complete path) or a single file (complete path), return an array of ca for use in https options
  @param caChain can be a file full path or an array of files (full path) if you are using a CA chain.
  @returns {*} the CA cahin to be used as options in https requests